Check for write errors in standard out and exit with error

The underlying problem is that System.out is a PrintWriter and
as such it does not throw exceptions on error, but rather just
sets a flag and continues.

This changes replaces the use of System.out with a PrintWriter-like
writer that does not catch error, but instead throw them to the
caller.

Bug: 366243
Change-Id: I44405edc4416e943b87f09a0f6ed041c6c51b046

42 files changed, 439 insertions, 228 deletions

diff --git a/org.eclipse.jgit.pgm.test/META-INF/MANIFEST.MF b/org.eclipse.jgit.pgm.test/META-INF/MANIFEST.MF
index 0e8ebc6fa1..61007f98b2 100644
--- a/org.eclipse.jgit.pgm.test/META-INF/MANIFEST.MF
+++ b/org.eclipse.jgit.pgm.test/META-INF/MANIFEST.MF
@@ -15,6 +15,7 @@ Import-Package: org.eclipse.jgit.api;version="[2.1.0,2.2.0)",
  org.eclipse.jgit.revwalk;version="[2.1.0,2.2.0)",
  org.eclipse.jgit.storage.file;version="[2.1.0,2.2.0)",
  org.eclipse.jgit.util;version="[2.1.0,2.2.0)",
+ org.eclipse.jgit.util.io;version="[2.1.0,2.2.0)",
  org.hamcrest.core;bundle-version="[1.1.0,2.0.0)",
  org.junit;version="[4.4.0,5.0.0)",
  org.kohsuke.args4j;version="[2.0.12,2.1.0)",
diff --git a/org.eclipse.jgit.pgm.test/src/org/eclipse/jgit/pgm/CLIGitCommand.java b/org.eclipse.jgit.pgm.test/src/org/eclipse/jgit/pgm/CLIGitCommand.java
index 28339c71e3..78e752d44e 100644
--- a/org.eclipse.jgit.pgm.test/src/org/eclipse/jgit/pgm/CLIGitCommand.java
+++ b/org.eclipse.jgit.pgm.test/src/org/eclipse/jgit/pgm/CLIGitCommand.java
@@ -42,10 +42,7 @@
  */
 package org.eclipse.jgit.pgm;
 
-import java.io.BufferedWriter;
 import java.io.ByteArrayOutputStream;
-import java.io.OutputStreamWriter;
-import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -84,21 +81,20 @@ public class CLIGitCommand {
 		clp.parseArgument(argv);
 
 		final TextBuiltin cmd = bean.getSubcommand();
+		ByteArrayOutputStream baos = new ByteArrayOutputStream();
+		cmd.outs = baos;
 		if (cmd.requiresRepository())
 			cmd.init(db, null);
 		else
 			cmd.init(null, null);
-		ByteArrayOutputStream baos = new ByteArrayOutputStream();
-		cmd.out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
-				baos)));
 		try {
 			cmd.execute(bean.getArguments().toArray(
 					new String[bean.getArguments().size()]));
 		} catch (Die e) {
 			return IO.readLines(e.getMessage());
 		} finally {
-			if (cmd.out != null)
-				cmd.out.flush();
+			if (cmd.outw != null)
+				cmd.outw.flush();
 		}
 		return IO.readLines(baos.toString());
 	}
diff --git a/org.eclipse.jgit.pgm/META-INF/MANIFEST.MF b/org.eclipse.jgit.pgm/META-INF/MANIFEST.MF
index 0f837b2977..00946ee158 100644
--- a/org.eclipse.jgit.pgm/META-INF/MANIFEST.MF
+++ b/org.eclipse.jgit.pgm/META-INF/MANIFEST.MF
@@ -28,6 +28,7 @@ Import-Package: org.eclipse.jgit.api;version="[2.1.0,2.2.0)",
  org.eclipse.jgit.treewalk;version="[2.1.0,2.2.0)",
  org.eclipse.jgit.treewalk.filter;version="[2.1.0,2.2.0)",
  org.eclipse.jgit.util;version="[2.1.0,2.2.0)",
+ org.eclipse.jgit.util.io;version="[2.1.0,2.2.0)",
  org.kohsuke.args4j;version="[2.0.12,2.1.0)",
  org.kohsuke.args4j.spi;version="[2.0.12,2.1.0)"
 Bundle-ActivationPolicy: lazy
diff --git a/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/CLIText.properties b/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/CLIText.properties
index 0291f5ce26..9fb0eba8fb 100644
--- a/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/CLIText.properties
+++ b/org.eclipse.jgit.pgm/resources/org/eclipse/jgit/pgm/CLIText.properties
@@ -152,6 +152,7 @@ tagLabel=tag
 taggerInfo=Tagger: {0} <{1}>
 timeInMilliSeconds={0} ms
 tooManyRefsGiven=Too many refs given
+unknownIoErrorStdout=An unknown I/O error occurred on standard output
 unknownMergeStrategy=unknown merge strategy {0} specified
 unmergedPaths=Unmerged paths:
 unsupportedOperation=Unsupported operation: {0}
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/AbstractFetchCommand.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/AbstractFetchCommand.java
index 5d31637cc4..4633187d77 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/AbstractFetchCommand.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/AbstractFetchCommand.java
@@ -63,7 +63,7 @@ abstract class AbstractFetchCommand extends TextBuiltin {
 	@Option(name = "--verbose", aliases = { "-v" }, usage = "usage_beMoreVerbose")
 	private boolean verbose;
 
-	protected void showFetchResult(final FetchResult r) {
+	protected void showFetchResult(final FetchResult r) throws IOException {
 		ObjectReader reader = db.newObjectReader();
 		try {
 			boolean shownURI = false;
@@ -77,13 +77,13 @@ abstract class AbstractFetchCommand extends TextBuiltin {
 				final String dst = abbreviateRef(u.getLocalName(), true);
 
 				if (!shownURI) {
-					out.println(MessageFormat.format(CLIText.get().fromURI,
+					outw.println(MessageFormat.format(CLIText.get().fromURI,
 							r.getURI()));
 					shownURI = true;
 				}
 
-				out.format(" %c %-17s %-10s -> %s", type, longType, src, dst);
-				out.println();
+				outw.format(" %c %-17s %-10s -> %s", type, longType, src, dst);
+				outw.println();
 			}
 		} finally {
 			reader.release();
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/AmazonS3Client.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/AmazonS3Client.java
index cad4b63314..f137b10aca 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/AmazonS3Client.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/AmazonS3Client.java
@@ -86,21 +86,23 @@ class AmazonS3Client extends TextBuiltin {
 			int len = c.getContentLength();
 			final InputStream in = c.getInputStream();
 			try {
+				outw.flush();
 				final byte[] tmp = new byte[2048];
 				while (len > 0) {
 					final int n = in.read(tmp);
 					if (n < 0)
 						throw new EOFException(MessageFormat.format(CLIText.get().expectedNumberOfbytes, len));
-					System.out.write(tmp, 0, n);
+					outs.write(tmp, 0, n);
 					len -= n;
 				}
+				outs.flush();
 			} finally {
 				in.close();
 			}
 
 		} else if ("ls".equals(op) || "list".equals(op)) {
 			for (final String k : s3.list(bucket, key))
-				System.out.println(k);
+				outw.println(k);
 
 		} else if ("rm".equals(op) || "delete".equals(op)) {
 			s3.delete(bucket, key);
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Blame.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Blame.java
index 162f433ffa..a67c35d933 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Blame.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Blame.java
@@ -210,17 +210,18 @@ class Blame extends TextBuiltin {
 					authorWidth, dateWidth);
 
 			for (int line = begin; line < end; line++) {
-				out.print(abbreviate(blame.getSourceCommit(line)));
+				outw.print(abbreviate(blame.getSourceCommit(line)));
 				if (showSourcePath)
-					out.format(pathFmt, path(line));
+					outw.format(pathFmt, path(line));
 				if (showSourceLine)
-					out.format(numFmt, blame.getSourceLine(line) + 1);
+					outw.format(numFmt, blame.getSourceLine(line) + 1);
 				if (!noAuthor)
-					out.format(authorFmt, author(line), date(line));
-				out.format(lineFmt, line + 1);
-				out.flush();
-				blame.getResultContents().writeLine(System.out, line);
-				out.print('\n');
+					outw.format(authorFmt, author(line), date(line));
+				outw.format(lineFmt, line + 1);
+				outw.flush();
+				blame.getResultContents().writeLine(outs, line);
+				outs.flush();
+				outw.print('\n');
 			}
 		} finally {
 			generator.release();
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Branch.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Branch.java
index 5fb4a963e1..c20924d3a6 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Branch.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Branch.java
@@ -215,18 +215,18 @@ class Branch extends TextBuiltin {
 
 	private void printHead(final ObjectReader reader, final String ref,
 			final boolean isCurrent, final Ref refObj) throws Exception {
-		out.print(isCurrent ? '*' : ' ');
-		out.print(' ');
-		out.print(ref);
+		outw.print(isCurrent ? '*' : ' ');
+		outw.print(' ');
+		outw.print(ref);
 		if (verbose) {
 			final int spaces = maxNameLength - ref.length() + 1;
-			out.format("%" + spaces + "s", "");
+			outw.format("%" + spaces + "s", "");
 			final ObjectId objectId = refObj.getObjectId();
-			out.print(reader.abbreviate(objectId).name());
-			out.print(' ');
-			out.print(rw.parseCommit(objectId).getShortMessage());
+			outw.print(reader.abbreviate(objectId).name());
+			outw.print(' ');
+			outw.print(rw.parseCommit(objectId).getShortMessage());
 		}
-		out.println();
+		outw.println();
 	}
 
 	private void delete(boolean force) throws IOException {
@@ -247,9 +247,9 @@ class Branch extends TextBuiltin {
 			} else if (result == Result.NEW)
 				throw die(MessageFormat.format(CLIText.get().branchNotFound, branch));
 			if (remote)
-				out.println(MessageFormat.format(CLIText.get().deletedRemoteBranch, branch));
+				outw.println(MessageFormat.format(CLIText.get().deletedRemoteBranch, branch));
 			else if (verbose)
-				out.println(MessageFormat.format(CLIText.get().deletedBranch, branch));
+				outw.println(MessageFormat.format(CLIText.get().deletedBranch, branch));
 		}
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/CLIText.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/CLIText.java
index 85b91ab948..ac83847233 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/CLIText.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/CLIText.java
@@ -217,6 +217,7 @@ public class CLIText extends TranslationBundle {
 	/***/ public String taggerInfo;
 	/***/ public String timeInMilliSeconds;
 	/***/ public String tooManyRefsGiven;
+	/***/ public char[] unknownIoErrorStdout;
 	/***/ public String unknownMergeStrategy;
 	/***/ public String unmergedPaths;
 	/***/ public String unsupportedOperation;
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Checkout.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Checkout.java
index ee1ded09a6..c356e184a4 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Checkout.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Checkout.java
@@ -84,20 +84,22 @@ class Checkout extends TextBuiltin {
 			String oldBranch = db.getBranch();
 			Ref ref = command.call();
 			if (Repository.shortenRefName(ref.getName()).equals(oldBranch)) {
-				out.println(MessageFormat.format(CLIText.get().alreadyOnBranch,
+				outw.println(MessageFormat.format(
+						CLIText.get().alreadyOnBranch,
 						name));
 				return;
 			}
 			if (createBranch)
-				out.println(MessageFormat.format(
+				outw.println(MessageFormat.format(
 						CLIText.get().switchedToNewBranch,
 						Repository.shortenRefName(ref.getName())));
 			else
-				out.println(MessageFormat.format(
+				outw.println(MessageFormat.format(
 						CLIText.get().switchedToBranch,
 						Repository.shortenRefName(ref.getName())));
 		} catch (RefNotFoundException e) {
-			out.println(MessageFormat.format(CLIText.get().pathspecDidNotMatch,
+			outw.println(MessageFormat.format(
+					CLIText.get().pathspecDidNotMatch,
 					name));
 		} catch (RefAlreadyExistsException e) {
 			throw die(MessageFormat.format(CLIText.get().branchAlreadyExists,
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java
index de430294fb..31d8ec8e12 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java
@@ -55,8 +55,6 @@ import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.dircache.DirCacheCheckout;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
-import org.eclipse.jgit.errors.NotSupportedException;
-import org.eclipse.jgit.errors.TransportException;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.RefComparator;
@@ -116,10 +114,10 @@ class Clone extends AbstractFetchCommand {
 		dstcfg.save();
 		db = dst;
 
-		out.print(MessageFormat.format(
+		outw.print(MessageFormat.format(
 				CLIText.get().initializedEmptyGitRepositoryIn, gitdir));
-		out.println();
-		out.flush();
+		outw.println();
+		outw.flush();
 
 		saveRemote(uri);
 		final FetchResult r = runFetch();
@@ -139,8 +137,7 @@ class Clone extends AbstractFetchCommand {
 		dstcfg.save();
 	}
 
-	private FetchResult runFetch() throws NotSupportedException,
-			URISyntaxException, TransportException {
+	private FetchResult runFetch() throws URISyntaxException, IOException {
 		final Transport tn = Transport.open(db, remoteName);
 		final FetchResult r;
 		try {
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Commit.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Commit.java
index dccf33de08..0963286e9f 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Commit.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Commit.java
@@ -109,7 +109,7 @@ class Commit extends TextBuiltin {
 			if (branchName.startsWith(Constants.R_HEADS))
 				branchName = branchName.substring(Constants.R_HEADS.length());
 		}
-		out.println("[" + branchName + " " + commit.name() + "] "
+		outw.println("[" + branchName + " " + commit.name() + "] "
 				+ commit.getShortMessage());
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Config.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Config.java
index f2cd920580..cf5539f747 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Config.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Config.java
@@ -103,7 +103,7 @@ class Config extends TextBuiltin {
 			Set<String> names = config.getNames(section);
 			for (String name : names) {
 				for (String value : config.getStringList(section, null, name))
-					out.println(section + "." + name + "=" + value);
+					outw.println(section + "." + name + "=" + value);
 			}
 			if (names.isEmpty()) {
 				for (String subsection : config.getSubsections(section)) {
@@ -111,7 +111,7 @@ class Config extends TextBuiltin {
 					for (String name : names) {
 						for (String value : config.getStringList(section,
 								subsection, name))
-							out.println(section + "." + subsection + "."
+							outw.println(section + "." + subsection + "."
 									+ name + "=" + value);
 					}
 				}
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Daemon.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Daemon.java
index 9b637cdb31..c75da9f89b 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Daemon.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Daemon.java
@@ -127,7 +127,7 @@ class Daemon extends TextBuiltin {
 
 		final FileResolver<DaemonClient> resolver = new FileResolver<DaemonClient>();
 		for (final File f : directory) {
-			out.println(MessageFormat.format(CLIText.get().exporting, f.getAbsolutePath()));
+			outw.println(MessageFormat.format(CLIText.get().exporting, f.getAbsolutePath()));
 			resolver.exportDirectory(f);
 		}
 		resolver.setExportAll(exportAll);
@@ -152,7 +152,7 @@ class Daemon extends TextBuiltin {
 			service(d, n).setOverridable(false);
 
 		d.start();
-		out.println(MessageFormat.format(CLIText.get().listeningOn, d.getAddress()));
+		outw.println(MessageFormat.format(CLIText.get().listeningOn, d.getAddress()));
 	}
 
 	private DaemonService service(final org.eclipse.jgit.transport.Daemon d,
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Diff.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Diff.java
index 5cc058950c..56564c71c2 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Diff.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Diff.java
@@ -49,7 +49,7 @@ import static org.eclipse.jgit.lib.Constants.HEAD;
 import static org.eclipse.jgit.lib.Constants.OBJECT_ID_STRING_LENGTH;
 
 import java.io.BufferedOutputStream;
-import java.io.PrintWriter;
+import java.io.IOException;
 import java.text.MessageFormat;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
@@ -69,13 +69,14 @@ import org.eclipse.jgit.treewalk.AbstractTreeIterator;
 import org.eclipse.jgit.treewalk.CanonicalTreeParser;
 import org.eclipse.jgit.treewalk.FileTreeIterator;
 import org.eclipse.jgit.treewalk.filter.TreeFilter;
+import org.eclipse.jgit.util.io.ThrowingPrintWriter;
 import org.kohsuke.args4j.Argument;
 import org.kohsuke.args4j.Option;
 
 @Command(common = true, usage = "usage_ShowDiffs")
 class Diff extends TextBuiltin {
 	private final DiffFormatter diffFmt = new DiffFormatter( //
-			new BufferedOutputStream(System.out));
+			new BufferedOutputStream(outs));
 
 	@Argument(index = 0, metaVar = "metaVar_treeish")
 	private AbstractTreeIterator oldTree;
@@ -202,8 +203,8 @@ class Diff extends TextBuiltin {
 			}
 
 			if (showNameAndStatusOnly) {
-				nameStatus(out, diffFmt.scan(oldTree, newTree));
-				out.flush();
+				nameStatus(outw, diffFmt.scan(oldTree, newTree));
+				outw.flush();
 
 			} else {
 				diffFmt.format(oldTree, newTree);
@@ -214,7 +215,8 @@ class Diff extends TextBuiltin {
 		}
 	}
 
-	static void nameStatus(PrintWriter out, List<DiffEntry> files) {
+	static void nameStatus(ThrowingPrintWriter out, List<DiffEntry> files)
+			throws IOException {
 		for (DiffEntry ent : files) {
 			switch (ent.getChangeType()) {
 			case ADD:
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/DiffTree.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/DiffTree.java
index ed82c4b862..018bad0694 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/DiffTree.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/DiffTree.java
@@ -82,19 +82,19 @@ class DiffTree extends TextBuiltin {
 		final int nTree = walk.getTreeCount();
 		while (walk.next()) {
 			for (int i = 1; i < nTree; i++)
-				out.print(':');
+				outw.print(':');
 			for (int i = 0; i < nTree; i++) {
 				final FileMode m = walk.getFileMode(i);
 				final String s = m.toString();
 				for (int pad = 6 - s.length(); pad > 0; pad--)
-					out.print('0');
-				out.print(s);
-				out.print(' ');
+					outw.print('0');
+				outw.print(s);
+				outw.print(' ');
 			}
 
 			for (int i = 0; i < nTree; i++) {
-				out.print(walk.getObjectId(i).name());
-				out.print(' ');
+				outw.print(walk.getObjectId(i).name());
+				outw.print(' ');
 			}
 
 			char chg = 'M';
@@ -108,11 +108,11 @@ class DiffTree extends TextBuiltin {
 				else if (m0 != m1 && walk.idEqual(0, 1))
 					chg = 'T';
 			}
-			out.print(chg);
+			outw.print(chg);
 
-			out.print('\t');
-			out.print(walk.getPathString());
-			out.println();
+			outw.print('\t');
+			outw.print(walk.getPathString());
+			outw.println();
 		}
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Init.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Init.java
index e1e38e5bc8..ab498873d9 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Init.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Init.java
@@ -72,7 +72,7 @@ class Init extends TextBuiltin {
 		if (gitdir != null)
 			command.setDirectory(new File(gitdir));
 		Repository repository = command.call().getRepository();
-		out.println(MessageFormat.format(
+		outw.println(MessageFormat.format(
 				CLIText.get().initializedEmptyGitRepositoryIn, repository
 						.getDirectory().getAbsolutePath()));
 	}
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Log.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Log.java
index f0b2ca90c8..987021e4f9 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Log.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Log.java
@@ -80,7 +80,7 @@ class Log extends RevWalkTextBuiltin {
 			Format.DEFAULT);
 
 	private final DiffFormatter diffFmt = new DiffFormatter( //
-			new BufferedOutputStream(System.out));
+			new BufferedOutputStream(outs));
 
 	private Map<AnyObjectId, Set<Ref>> allRefsByPeeledObjectId;
 
@@ -231,43 +231,43 @@ class Log extends RevWalkTextBuiltin {
 
 	@Override
 	protected void show(final RevCommit c) throws Exception {
-		out.print(CLIText.get().commitLabel);
-		out.print(" ");
-		c.getId().copyTo(outbuffer, out);
+		outw.print(CLIText.get().commitLabel);
+		outw.print(" ");
+		c.getId().copyTo(outbuffer, outw);
 		if (decorate) {
 			Collection<Ref> list = allRefsByPeeledObjectId.get(c);
 			if (list != null) {
-				out.print(" (");
+				outw.print(" (");
 				for (Iterator<Ref> i = list.iterator(); i.hasNext(); ) {
-					out.print(i.next().getName());
+					outw.print(i.next().getName());
 					if (i.hasNext())
-						out.print(" ");
+						outw.print(" ");
 				}
-				out.print(")");
+				outw.print(")");
 			}
 		}
-		out.println();
+		outw.println();
 
 		final PersonIdent author = c.getAuthorIdent();
-		out.println(MessageFormat.format(CLIText.get().authorInfo, author.getName(), author.getEmailAddress()));
-		out.println(MessageFormat.format(CLIText.get().dateInfo,
+		outw.println(MessageFormat.format(CLIText.get().authorInfo, author.getName(), author.getEmailAddress()));
+		outw.println(MessageFormat.format(CLIText.get().dateInfo,
 				dateFormatter.formatDate(author)));
 
-		out.println();
+		outw.println();
 		final String[] lines = c.getFullMessage().split("\n");
 		for (final String s : lines) {
-			out.print("    ");
-			out.print(s);
-			out.println();
+			outw.print("    ");
+			outw.print(s);
+			outw.println();
 		}
 
-		out.println();
+		outw.println();
 		if (showNotes(c))
-			out.println();
+			outw.println();
 
 		if (c.getParentCount() == 1 && (showNameAndStatusOnly || showPatch))
 			showDiff(c);
-		out.flush();
+		outw.flush();
 	}
 
 	/**
@@ -315,23 +315,23 @@ class Log extends RevWalkTextBuiltin {
 		if (blobId == null)
 			return false;
 		if (emptyLine)
-			out.println();
-		out.print("Notes");
+			outw.println();
+		outw.print("Notes");
 		if (label != null) {
-			out.print(" (");
-			out.print(label);
-			out.print(")");
+			outw.print(" (");
+			outw.print(label);
+			outw.print(")");
 		}
-		out.println(":");
+		outw.println(":");
 		try {
 			RawText rawText = new RawText(argWalk.getObjectReader()
 					.open(blobId).getCachedBytes(Integer.MAX_VALUE));
 			for (int i = 0; i < rawText.size(); i++) {
-				out.print("    ");
-				out.println(rawText.getString(i));
+				outw.print("    ");
+				outw.println(rawText.getString(i));
 			}
 		} catch (LargeObjectException e) {
-			out.println(MessageFormat.format(
+			outw.println(MessageFormat.format(
 					CLIText.get().noteObjectTooLargeToPrint, blobId.name()));
 		}
 		return true;
@@ -342,12 +342,12 @@ class Log extends RevWalkTextBuiltin {
 		final RevTree b = c.getTree();
 
 		if (showNameAndStatusOnly)
-			Diff.nameStatus(out, diffFmt.scan(a, b));
+			Diff.nameStatus(outw, diffFmt.scan(a, b));
 		else {
-			out.flush();
+			outw.flush();
 			diffFmt.format(a, b);
 			diffFmt.flush();
 		}
-		out.println();
+		outw.println();
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/LsRemote.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/LsRemote.java
index e750e2dea8..d59451c55e 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/LsRemote.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/LsRemote.java
@@ -45,6 +45,8 @@
 
 package org.eclipse.jgit.pgm;
 
+import java.io.IOException;
+
 import org.kohsuke.args4j.Argument;
 import org.kohsuke.args4j.Option;
 import org.eclipse.jgit.lib.AnyObjectId;
@@ -77,10 +79,11 @@ class LsRemote extends TextBuiltin {
 		}
 	}
 
-	private void show(final AnyObjectId id, final String name) {
-		out.print(id.name());
-		out.print('\t');
-		out.print(name);
-		out.println();
+	private void show(final AnyObjectId id, final String name)
+			throws IOException {
+		outw.print(id.name());
+		outw.print('\t');
+		outw.print(name);
+		outw.println();
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/LsTree.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/LsTree.java
index 6878d8ef48..16480d9dbf 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/LsTree.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/LsTree.java
@@ -68,17 +68,17 @@ class LsTree extends TextBuiltin {
 		while (walk.next()) {
 			final FileMode mode = walk.getFileMode(0);
 			if (mode == FileMode.TREE)
-				out.print('0');
-			out.print(mode);
-			out.print(' ');
-			out.print(Constants.typeString(mode.getObjectType()));
+				outw.print('0');
+			outw.print(mode);
+			outw.print(' ');
+			outw.print(Constants.typeString(mode.getObjectType()));
 
-			out.print(' ');
-			out.print(walk.getObjectId(0).name());
+			outw.print(' ');
+			outw.print(walk.getObjectId(0).name());
 
-			out.print('\t');
-			out.print(walk.getPathString());
-			out.println();
+			outw.print('\t');
+			outw.print(walk.getPathString());
+			outw.println();
 		}
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Main.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Main.java
index 654eed2cd9..6c5cd2767c 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Main.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Main.java
@@ -137,6 +137,15 @@ public class Main {
 			err.printStackTrace();
 			System.exit(1);
 		}
+		if (System.out.checkError()) {
+			System.err.println(CLIText.get().unknownIoErrorStdout);
+			System.exit(1);
+		}
+		if (System.err.checkError()) {
+			// No idea how to present an error here, most likely disk full or
+			// broken pipe
+			System.exit(1);
+		}
 	}
 
 	private void execute(final String[] argv) throws Exception {
@@ -190,8 +199,8 @@ public class Main {
 		try {
 			cmd.execute(arguments.toArray(new String[arguments.size()]));
 		} finally {
-			if (cmd.out != null)
-				cmd.out.flush();
+			if (cmd.outw != null)
+				cmd.outw.flush();
 		}
 	}
 
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Merge.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Merge.java
index 4cd82b8225..da0f8b868a 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Merge.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Merge.java
@@ -88,13 +88,13 @@ class Merge extends TextBuiltin {
 		switch (result.getMergeStatus()) {
 		case ALREADY_UP_TO_DATE:
 		case FAST_FORWARD:
-			out.println(result.getMergeStatus().toString());
+			outw.println(result.getMergeStatus().toString());
 			break;
 		case CONFLICTING:
 			for (String collidingPath : result.getConflicts().keySet())
-				out.println(MessageFormat.format(CLIText.get().mergeConflict,
+				outw.println(MessageFormat.format(CLIText.get().mergeConflict,
 						collidingPath));
-			out.println(CLIText.get().mergeFailed);
+			outw.println(CLIText.get().mergeFailed);
 			break;
 		case FAILED:
 			for (Map.Entry<String, MergeFailureReason> entry : result
@@ -102,21 +102,21 @@ class Merge extends TextBuiltin {
 				switch (entry.getValue()) {
 				case DIRTY_WORKTREE:
 				case DIRTY_INDEX:
-					out.println(CLIText.get().dontOverwriteLocalChanges);
-					out.println("        " + entry.getKey());
+					outw.println(CLIText.get().dontOverwriteLocalChanges);
+					outw.println("        " + entry.getKey());
 					break;
 				case COULD_NOT_DELETE:
-					out.println(CLIText.get().cannotDeleteFile);
-					out.println("        " + entry.getKey());
+					outw.println(CLIText.get().cannotDeleteFile);
+					outw.println("        " + entry.getKey());
 					break;
 				}
 			break;
 		case MERGED:
-			out.println(MessageFormat.format(CLIText.get().mergeMadeBy,
+			outw.println(MessageFormat.format(CLIText.get().mergeMadeBy,
 					mergeStrategy.getName()));
 			break;
 		case NOT_SUPPORTED:
-			out.println(MessageFormat.format(
+			outw.println(MessageFormat.format(
 					CLIText.get().unsupportedOperation, result.toString()));
 		}
 	}
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/MergeBase.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/MergeBase.java
index f59fd43158..34aa9b2fed 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/MergeBase.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/MergeBase.java
@@ -74,7 +74,7 @@ class MergeBase extends TextBuiltin {
 			final RevCommit b = argWalk.next();
 			if (b == null)
 				break;
-			out.println(b.getId().name());
+			outw.println(b.getId().name());
 		}
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Push.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Push.java
index 677e7332c3..f466517250 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Push.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Push.java
@@ -132,7 +132,7 @@ class Push extends TextBuiltin {
 	}
 
 	private void printPushResult(final ObjectReader reader, final URIish uri,
-			final PushResult result) {
+			final PushResult result) throws IOException {
 		shownURI = false;
 		boolean everythingUpToDate = true;
 
@@ -160,14 +160,15 @@ class Push extends TextBuiltin {
 
 		AbstractFetchCommand.showRemoteMessages(result.getMessages());
 		if (everythingUpToDate)
-			out.println(CLIText.get().everythingUpToDate);
+			outw.println(CLIText.get().everythingUpToDate);
 	}
 
 	private void printRefUpdateResult(final ObjectReader reader,
-			final URIish uri, final PushResult result, final RemoteRefUpdate rru) {
+			final URIish uri, final PushResult result, final RemoteRefUpdate rru)
+			throws IOException {
 		if (!shownURI) {
 			shownURI = true;
-			out.println(MessageFormat.format(CLIText.get().pushTo, uri));
+			outw.println(MessageFormat.format(CLIText.get().pushTo, uri));
 		}
 
 		final String remoteName = rru.getRemoteName();
@@ -247,16 +248,17 @@ class Push extends TextBuiltin {
 	}
 
 	private void printUpdateLine(final char flag, final String summary,
-			final String srcRef, final String destRef, final String message) {
-		out.format(" %c %-17s", flag, summary);
+			final String srcRef, final String destRef, final String message)
+			throws IOException {
+		outw.format(" %c %-17s", flag, summary);
 
 		if (srcRef != null)
-			out.format(" %s ->", abbreviateRef(srcRef, true));
-		out.format(" %s", abbreviateRef(destRef, true));
+			outw.format(" %s ->", abbreviateRef(srcRef, true));
+		outw.format(" %s", abbreviateRef(destRef, true));
 
 		if (message != null)
-			out.format(" (%s)", message);
+			outw.format(" (%s)", message);
 
-		out.println();
+		outw.println();
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ReceivePack.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ReceivePack.java
index 7a27617220..dd6de1d667 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ReceivePack.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ReceivePack.java
@@ -75,6 +75,6 @@ class ReceivePack extends TextBuiltin {
 		}
 
 		rp = new org.eclipse.jgit.transport.ReceivePack(db);
-		rp.receive(System.in, System.out, System.err);
+		rp.receive(System.in, outs, System.err);
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevList.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevList.java
index 1b8c180f91..bab502b791 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevList.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevList.java
@@ -53,29 +53,29 @@ class RevList extends RevWalkTextBuiltin {
 	@Override
 	protected void show(final RevCommit c) throws Exception {
 		if (c.has(RevFlag.UNINTERESTING))
-			out.print('-');
-		c.getId().copyTo(outbuffer, out);
+			outw.print('-');
+		c.getId().copyTo(outbuffer, outw);
 		if (parents)
 			for (int i = 0; i < c.getParentCount(); i++) {
-				out.print(' ');
-				c.getParent(i).getId().copyTo(outbuffer, out);
+				outw.print(' ');
+				c.getParent(i).getId().copyTo(outbuffer, outw);
 			}
-		out.println();
+		outw.println();
 	}
 
 	@Override
 	protected void show(final ObjectWalk ow, final RevObject obj)
 			throws Exception {
 		if (obj.has(RevFlag.UNINTERESTING))
-			out.print('-');
-		obj.getId().copyTo(outbuffer, out);
+			outw.print('-');
+		obj.getId().copyTo(outbuffer, outw);
 		final String path = ow.getPathString();
 		if (path != null) {
-			out.print(' ');
-			out.print(path);
+			outw.print(' ');
+			outw.print(path);
 		} else if (obj instanceof RevTree)
-			out.print(' ');
-		out.println();
+			outw.print(' ');
+		outw.println();
 
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevParse.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevParse.java
index 98eb2ce86b..b564107b9e 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevParse.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/RevParse.java
@@ -65,10 +65,10 @@ class RevParse extends TextBuiltin {
 		if (all) {
 			Map<String, Ref> allRefs = db.getAllRefs();
 			for (final Ref r : allRefs.values())
-				out.println(r.getObjectId().name());
+				outw.println(r.getObjectId().name());
 		} else {
 			for (final ObjectId o : commits)
-				out.println(o.name());
+				outw.println(o.name());
 		}
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Show.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Show.java
index 5eeb214920..13dad7a9a0 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Show.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Show.java
@@ -198,16 +198,16 @@ class Show extends TextBuiltin {
 					break;
 
 				case Constants.OBJ_TREE:
-					out.print("tree ");
-					out.print(objectName);
-					out.println();
-					out.println();
+					outw.print("tree ");
+					outw.print(objectName);
+					outw.println();
+					outw.println();
 					show((RevTree) obj);
 					break;
 
 				case Constants.OBJ_BLOB:
 					db.open(obj, obj.getType()).copyTo(System.out);
-					System.out.flush();
+					outw.flush();
 					break;
 
 				default:
@@ -223,32 +223,32 @@ class Show extends TextBuiltin {
 		}
 	}
 
-	private void show(RevTag tag) {
-		out.print(CLIText.get().tagLabel);
-		out.print(" ");
-		out.print(tag.getTagName());
-		out.println();
+	private void show(RevTag tag) throws IOException {
+		outw.print(CLIText.get().tagLabel);
+		outw.print(" ");
+		outw.print(tag.getTagName());
+		outw.println();
 
 		final PersonIdent tagger = tag.getTaggerIdent();
 		if (tagger != null) {
-			out.println(MessageFormat.format(CLIText.get().taggerInfo,
+			outw.println(MessageFormat.format(CLIText.get().taggerInfo,
 					tagger.getName(), tagger.getEmailAddress()));
 
 			final TimeZone taggerTZ = tagger.getTimeZone();
 			fmt.setTimeZone(taggerTZ != null ? taggerTZ : myTZ);
-			out.println(MessageFormat.format(CLIText.get().dateInfo,
+			outw.println(MessageFormat.format(CLIText.get().dateInfo,
 					fmt.format(tagger.getWhen())));
 		}
 
-		out.println();
+		outw.println();
 		final String[] lines = tag.getFullMessage().split("\n");
 		for (final String s : lines) {
-			out.print("    ");
-			out.print(s);
-			out.println();
+			outw.print("    ");
+			outw.print(s);
+			outw.println();
 		}
 
-		out.println();
+		outw.println();
 	}
 
 	private void show(RevTree obj) throws MissingObjectException,
@@ -258,45 +258,45 @@ class Show extends TextBuiltin {
 		walk.addTree(obj);
 
 		while (walk.next()) {
-			out.print(walk.getPathString());
+			outw.print(walk.getPathString());
 			final FileMode mode = walk.getFileMode(0);
 			if (mode == FileMode.TREE)
-				out.print('/');
-			out.println();
+				outw.print("/");
+			outw.println();
 		}
 	}
 
 	private void show(RevWalk rw, final RevCommit c) throws Exception {
 		char[] outbuffer = new char[Constants.OBJECT_ID_LENGTH * 2];
 
-		out.print(CLIText.get().commitLabel);
-		out.print(" ");
-		c.getId().copyTo(outbuffer, out);
-		out.println();
+		outw.print(CLIText.get().commitLabel);
+		outw.print(" ");
+		c.getId().copyTo(outbuffer, outw);
+		outw.println();
 
 		final PersonIdent author = c.getAuthorIdent();
-		out.println(MessageFormat.format(CLIText.get().authorInfo,
+		outw.println(MessageFormat.format(CLIText.get().authorInfo,
 				author.getName(), author.getEmailAddress()));
 
 		final TimeZone authorTZ = author.getTimeZone();
 		fmt.setTimeZone(authorTZ != null ? authorTZ : myTZ);
-		out.println(MessageFormat.format(CLIText.get().dateInfo,
+		outw.println(MessageFormat.format(CLIText.get().dateInfo,
 				fmt.format(author.getWhen())));
 
-		out.println();
+		outw.println();
 		final String[] lines = c.getFullMessage().split("\n");
 		for (final String s : lines) {
-			out.print("    ");
-			out.print(s);
-			out.println();
+			outw.print("    ");
+			outw.print(s);
+			outw.println();
 		}
 
-		out.println();
+		outw.println();
 		if (c.getParentCount() == 1) {
 			rw.parseHeaders(c.getParent(0));
 			showDiff(c);
 		}
-		out.flush();
+		outw.flush();
 	}
 
 	private void showDiff(RevCommit c) throws IOException {
@@ -304,12 +304,12 @@ class Show extends TextBuiltin {
 		final RevTree b = c.getTree();
 
 		if (showNameAndStatusOnly)
-			Diff.nameStatus(out, diffFmt.scan(a, b));
+			Diff.nameStatus(outw, diffFmt.scan(a, b));
 		else {
-			out.flush();
+			outw.flush();
 			diffFmt.format(a, b);
 			diffFmt.flush();
 		}
-		out.println();
+		outw.println();
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ShowRef.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ShowRef.java
index d34f373db2..3e0f661097 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ShowRef.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/ShowRef.java
@@ -45,6 +45,7 @@
 
 package org.eclipse.jgit.pgm;
 
+import java.io.IOException;
 import java.util.Map;
 import java.util.SortedMap;
 
@@ -71,10 +72,11 @@ class ShowRef extends TextBuiltin {
 		return RefComparator.sort(all.values());
 	}
 
-	private void show(final AnyObjectId id, final String name) {
-		out.print(id.name());
-		out.print('\t');
-		out.print(name);
-		out.println();
+	private void show(final AnyObjectId id, final String name)
+			throws IOException {
+		outw.print(id.name());
+		outw.print('\t');
+		outw.print(name);
+		outw.println();
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Tag.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Tag.java
index 1489e47d1c..81143f6b86 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Tag.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Tag.java
@@ -91,7 +91,7 @@ class Tag extends TextBuiltin {
 			ListTagCommand command = git.tagList();
 			List<Ref> list = command.call();
 			for (Ref ref : list) {
-				out.println(Repository.shortenRefName(ref.getName()));
+				outw.println(Repository.shortenRefName(ref.getName()));
 			}
 		}
 	}
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/TextBuiltin.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/TextBuiltin.java
index 2988dfc54b..fe8907bc20 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/TextBuiltin.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/TextBuiltin.java
@@ -49,7 +49,10 @@ import static org.eclipse.jgit.lib.Constants.R_REMOTES;
 import static org.eclipse.jgit.lib.Constants.R_TAGS;
 
 import java.io.BufferedWriter;
+import java.io.FileDescriptor;
+import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.text.MessageFormat;
@@ -59,6 +62,7 @@ import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.pgm.opt.CmdLineParser;
 import org.eclipse.jgit.revwalk.RevWalk;
+import org.eclipse.jgit.util.io.ThrowingPrintWriter;
 import org.kohsuke.args4j.CmdLineException;
 import org.kohsuke.args4j.Option;
 
@@ -79,7 +83,17 @@ public abstract class TextBuiltin {
 	@Option(name = "--help", usage = "usage_displayThisHelpText", aliases = { "-h" })
 	private boolean help;
 
+	/** Writer to output to, typically this is standard output. */
+	protected ThrowingPrintWriter outw;
+
 	/** Stream to output to, typically this is standard output. */
+	protected OutputStream outs;
+
+	/**
+	 * Stream to output to, typically this is standard output.
+	 *
+	 * @deprecated Use outw instead
+	 */
 	protected PrintWriter out;
 
 	/** Git repository the command was invoked within. */
@@ -114,12 +128,16 @@ public abstract class TextBuiltin {
 			final String outputEncoding = repository != null ? repository
 					.getConfig()
 					.getString("i18n", null, "logOutputEncoding") : null;
+			if (outs == null)
+				outs = new FileOutputStream(FileDescriptor.out);
+			BufferedWriter bufw;
 			if (outputEncoding != null)
-				out = new PrintWriter(new BufferedWriter(
-						new OutputStreamWriter(System.out, outputEncoding)));
+				bufw = new BufferedWriter(new OutputStreamWriter(outs,
+						outputEncoding));
 			else
-				out = new PrintWriter(new BufferedWriter(
-						new OutputStreamWriter(System.out)));
+				bufw = new BufferedWriter(new OutputStreamWriter(outs));
+			out = new PrintWriter(bufw);
+			outw = new ThrowingPrintWriter(bufw);
 		} catch (IOException e) {
 			throw die(CLIText.get().cannotCreateOutputStream);
 		}
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/UploadPack.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/UploadPack.java
index d4e2bcec76..df7f1c3c8c 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/UploadPack.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/UploadPack.java
@@ -81,6 +81,6 @@ class UploadPack extends TextBuiltin {
 		up = new org.eclipse.jgit.transport.UploadPack(db);
 		if (0 <= timeout)
 			up.setTimeout(timeout);
-		up.upload(System.in, System.out, System.err);
+		up.upload(System.in, outs, System.err);
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Version.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Version.java
index 9b51b871fc..cd7f5116b8 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Version.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Version.java
@@ -53,7 +53,7 @@ class Version extends TextBuiltin {
 		if (pkg == null || pkg.getImplementationVersion() == null)
 			throw die(CLIText.get().cannotReadPackageInformation);
 
-		out.println(MessageFormat.format(CLIText.get().jgitVersion, pkg.getImplementationVersion()));
+		outw.println(MessageFormat.format(CLIText.get().jgitVersion, pkg.getImplementationVersion()));
 	}
 
 	@Override
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/DiffAlgorithms.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/DiffAlgorithms.java
index f98cdfa4af..ef297322df 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/DiffAlgorithms.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/DiffAlgorithms.java
@@ -245,29 +245,29 @@ class DiffAlgorithms extends TextBuiltin {
 			File parent = db.getDirectory().getParentFile();
 			if (name.equals(Constants.DOT_GIT) && parent != null)
 				name = parent.getName();
-			out.println(name + ": start at " + startId.name());
+			outw.println(name + ": start at " + startId.name());
 		}
 
-		out.format("  %12d files,     %8d commits\n", files, commits);
-		out.format("  N=%10d min lines, %8d max lines\n", minN, maxN);
+		outw.format("  %12d files,     %8d commits\n", files, commits);
+		outw.format("  N=%10d min lines, %8d max lines\n", minN, maxN);
 
-		out.format("%-25s %12s ( %12s  %12s )\n", //
+		outw.format("%-25s %12s ( %12s  %12s )\n", //
 				"Algorithm", "Time(ns)", "Time(ns) on", "Time(ns) on");
-		out.format("%-25s %12s ( %12s  %12s )\n", //
+		outw.format("%-25s %12s ( %12s  %12s )\n", //
 				"", "", "N=" + minN, "N=" + maxN);
-		out.println("-----------------------------------------------------"
+		outw.println("-----------------------------------------------------"
 				+ "----------------");
 
 		for (Test test : all) {
-			out.format("%-25s %12d ( %12d  %12d )", //
+			outw.format("%-25s %12d ( %12d  %12d )", //
 					test.algorithm.name, //
 					test.runningTimeNanos, //
 					test.minN.runningTimeNanos, //
 					test.maxN.runningTimeNanos);
-			out.println();
+			outw.println();
 		}
-		out.println();
-		out.flush();
+		outw.println();
+		outw.flush();
 	}
 
 	private static boolean isFile(TreeWalk tw, int ithTree) {
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/MakeCacheTree.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/MakeCacheTree.java
index 709b45a17b..3961a7c156 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/MakeCacheTree.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/MakeCacheTree.java
@@ -44,6 +44,7 @@
 
 package org.eclipse.jgit.pgm.debug;
 
+import java.io.IOException;
 import java.text.MessageFormat;
 
 import org.eclipse.jgit.dircache.DirCache;
@@ -59,8 +60,8 @@ class MakeCacheTree extends TextBuiltin {
 		show(tree);
 	}
 
-	private void show(final DirCacheTree tree) {
-		out.println(MessageFormat.format(CLIText.get().cacheTreePathInfo
+	private void show(final DirCacheTree tree) throws IOException {
+		outw.println(MessageFormat.format(CLIText.get().cacheTreePathInfo
 				, tree.getPathString(), tree.getEntrySpan(), tree.getChildCount()));
 
 		for (int i = 0; i < tree.getChildCount(); i++)
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ReadDirCache.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ReadDirCache.java
index 0ca050880e..83dacce6b5 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ReadDirCache.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ReadDirCache.java
@@ -57,7 +57,7 @@ class ReadDirCache extends TextBuiltin {
 		for (int i = 0; i < cnt; i++)
 			db.readDirCache();
 		final long end = System.currentTimeMillis();
-		out.print(" ");
-		out.println(MessageFormat.format(CLIText.get().averageMSPerRead, (end - start) / cnt));
+		outw.print(" ");
+		outw.println(MessageFormat.format(CLIText.get().averageMSPerRead, (end - start) / cnt));
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowCacheTree.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowCacheTree.java
index c49aefbf2f..7b4b36aa42 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowCacheTree.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowCacheTree.java
@@ -44,6 +44,7 @@
 
 package org.eclipse.jgit.pgm.debug;
 
+import java.io.IOException;
 import java.text.MessageFormat;
 
 import org.eclipse.jgit.dircache.DirCache;
@@ -61,8 +62,8 @@ class ShowCacheTree extends TextBuiltin {
 		show(tree);
 	}
 
-	private void show(final DirCacheTree tree) {
-		out.println(MessageFormat.format(CLIText.get().cacheTreePathInfo
+	private void show(final DirCacheTree tree) throws IOException {
+		outw.println(MessageFormat.format(CLIText.get().cacheTreePathInfo
 				, tree.getPathString(), tree.getEntrySpan(), tree.getChildCount()));
 
 		for (int i = 0; i < tree.getChildCount(); i++)
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowDirCache.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowDirCache.java
index fb3e3e65bf..a710103e9d 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowDirCache.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowDirCache.java
@@ -68,17 +68,17 @@ class ShowDirCache extends TextBuiltin {
 			final Date mtime = new Date(ent.getLastModified());
 			final int stage = ent.getStage();
 
-			out.print(mode);
-			out.format(" %6d", len);
-			out.print(' ');
-			out.print(fmt.format(mtime));
-			out.print(' ');
-			out.print(ent.getObjectId().name());
-			out.print(' ');
-			out.print(stage);
-			out.print('\t');
-			out.print(ent.getPathString());
-			out.println();
+			outw.print(mode);
+			outw.format(" %6d", len);
+			outw.print(' ');
+			outw.print(fmt.format(mtime));
+			outw.print(' ');
+			outw.print(ent.getObjectId().name());
+			outw.print(' ');
+			outw.print(stage);
+			outw.print('\t');
+			outw.print(ent.getPathString());
+			outw.println();
 		}
 	}
 }
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowPackDelta.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowPackDelta.java
index ddeec330f7..c852d41638 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowPackDelta.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/ShowPackDelta.java
@@ -87,7 +87,7 @@ class ShowPackDelta extends TextBuiltin {
 			throw die("Object " + obj.name() + " is not a delta");
 		}
 
-		out.println(BinaryDelta.format(delta));
+		outw.println(BinaryDelta.format(delta));
 	}
 
 	private byte[] getDelta(ObjectReader reader, RevObject obj)
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/TextHashFunctions.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/TextHashFunctions.java
index e7051a1bdb..ab80037da3 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/TextHashFunctions.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/TextHashFunctions.java
@@ -344,26 +344,26 @@ class TextHashFunctions extends TextBuiltin {
 			File parent = db.getDirectory().getParentFile();
 			if (name.equals(Constants.DOT_GIT) && parent != null)
 				name = parent.getName();
-			out.println(name + ":");
+			outw.println(name + ":");
 		}
-		out.format("  %6d files; %5d avg. unique lines/file\n", //
+		outw.format("  %6d files; %5d avg. unique lines/file\n", //
 				fileCnt, //
 				lineCnt / fileCnt);
-		out.format("%-20s %-15s %9s\n", "Hash", "Fold", "Max Len");
-		out.println("-----------------------------------------------");
+		outw.format("%-20s %-15s %9s\n", "Hash", "Fold", "Max Len");
+		outw.println("-----------------------------------------------");
 		String lastHashName = null;
 		for (Function fun : all) {
 			String hashName = fun.hash.name;
 			if (hashName.equals(lastHashName))
 				hashName = "";
-			out.format("%-20s %-15s %9d\n", //
+			outw.format("%-20s %-15s %9d\n", //
 					hashName, //
 					fun.fold.name, //
 					fun.maxChainLength);
 			lastHashName = fun.hash.name;
 		}
-		out.println();
-		out.flush();
+		outw.println();
+		outw.flush();
 	}
 
 	private void testOne(Function fun, RawText txt, int[] elements, int cnt) {
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/eclipse/Iplog.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/eclipse/Iplog.java
index 86b93a0f84..5784fecd8d 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/eclipse/Iplog.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/eclipse/Iplog.java
@@ -114,8 +114,8 @@ class Iplog extends TextBuiltin {
 				lf.unlock();
 			}
 		} else {
-			log.writeTo(System.out);
-			System.out.flush();
+			log.writeTo(outs);
+			outs.flush();
 		}
 	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/io/ThrowingPrintWriter.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/io/ThrowingPrintWriter.java
new file mode 100644
index 0000000000..1c5c2b6b48
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/io/ThrowingPrintWriter.java
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2012, Robin Rosenberg <robin.rosenberg@dewire.com>
+ * and other copyright owners as documented in the project's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package org.eclipse.jgit.util.io;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
+
+import org.eclipse.jgit.util.SystemReader;
+
+/**
+ * An alternative PrintWriter that doesn't catch exceptions.
+ */
+public class ThrowingPrintWriter extends Writer {
+
+	private final Writer out;
+
+	private final String LF;
+
+	/**
+	 * Construct a JGitPrintWriter
+	 *
+	 * @param out
+	 *            the underlying {@link Writer}
+	 */
+	public ThrowingPrintWriter(Writer out) {
+		this.out = out;
+		LF = AccessController.doPrivileged(new PrivilegedAction<String>() {
+			public String run() {
+				return SystemReader.getInstance().getProperty("line.separator");
+			}
+		});
+	}
+
+	@Override
+	public void write(char[] cbuf, int off, int len) throws IOException {
+		out.write(cbuf, off, len);
+	}
+
+	@Override
+	public void flush() throws IOException {
+		out.flush();
+	}
+
+	@Override
+	public void close() throws IOException {
+		out.close();
+	}
+
+	/**
+	 * Print a string and terminate with a line feed.
+	 *
+	 * @param s
+	 * @throws IOException
+	 */
+	public void println(String s) throws IOException {
+		print(s + LF);
+	}
+
+	/**
+	 * Print a platform dependent new line
+	 *
+	 * @throws IOException
+	 */
+	public void println() throws IOException {
+		print(LF);
+	}
+
+	/**
+	 * Print a char
+	 *
+	 * @param value
+	 * @throws IOException
+	 */
+	public void print(char value) throws IOException {
+		print(String.valueOf(value));
+	}
+
+	/**
+	 * Print an int as string
+	 *
+	 * @param value
+	 * @throws IOException
+	 */
+	public void print(int value) throws IOException {
+		print(String.valueOf(value));
+	}
+
+	/**
+	 * Print a long as string
+	 *
+	 * @param value
+	 * @throws IOException
+	 */
+	public void print(long value) throws IOException {
+		print(String.valueOf(value));
+	}
+
+	/**
+	 * Print a short as string
+	 *
+	 * @param value
+	 * @throws IOException
+	 */
+	public void print(short value) throws IOException {
+		print(String.valueOf(value));
+	}
+
+	/**
+	 * Print a formatted message according to
+	 * {@link String#format(String, Object...)}.
+	 *
+	 * @param fmt
+	 * @param args
+	 * @throws IOException
+	 */
+	public void format(String fmt, Object... args) throws IOException {
+		print(String.format(fmt, args));
+	}
+
+	/**
+	 * Print an object's toString representations
+	 *
+	 * @param any
+	 * @throws IOException
+	 */
+	public void print(Object any) throws IOException {
+		out.write(String.valueOf(any));
+	}
+}