Usage message clean-up, take #2

There were some problems with the usage message clean-up patch
series. I hadn't realised that subdirectory aware scripts can't source
git-sh-setup. I propose that we change this and let the scripts which
are subdirectory aware set a variable, SUBDIRECTORY_OK, before they
source git-sh-setup.

The scripts will also set USAGE and possibly LONG_USAGE before they
source git-sh-setup. If LONG_USAGE isn't set it defaults to USAGE.

If we go this way it's easy to catch --help in git-sh-setup, print the
(long) usage message to stdout and exit cleanly. git-sh-setup can
define a 'usage' shell function which can be called by the scripts to
print the short usage string to stderr and exit non-cleanly. It will
also be easy to change $0 to basename $0 or something else, if would
like to do that sometime in the future.

What follows is a patch to convert a couple of the commands to this
style. If it's ok with everyone to do it this way I will convert the
rest of the scripts too.

[jc: thrown in to proposed updates queue for comments.]

Signed-off-by: Junio C Hamano <junkio@cox.net>

4 files changed, 56 insertions, 34 deletions

diff --git a/git-bisect.sh b/git-bisect.sh
index 05dae8ad13..51e1e4417d 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -1,4 +1,15 @@
 #!/bin/sh
+
+USAGE='[start|bad|good|next|reset|visualize]'
+LONG_USAGE='git bisect start [<pathspec>]	reset bisect state and start bisection.
+git bisect bad [<rev>]		mark <rev> a known-bad revision.
+git bisect good [<rev>...]	mark <rev>... known-good revisions.
+git bisect next			find next bisection to test and check it out.
+git bisect reset [<branch>]	finish bisection search and go back to branch.
+git bisect visualize            show bisect status in gitk.
+git bisect replay <logfile>	replay bisection log
+git bisect log			show bisect log.'
+
 . git-sh-setup
 
 sq() {
@@ -11,19 +22,6 @@ sq() {
 	' "$@"
 }
 
-usage() {
-    echo >&2 'usage: git bisect [start|bad|good|next|reset|visualize]
-git bisect start [<pathspec>]	reset bisect state and start bisection.
-git bisect bad [<rev>]		mark <rev> a known-bad revision.
-git bisect good [<rev>...]	mark <rev>... known-good revisions.
-git bisect next			find next bisection to test and check it out.
-git bisect reset [<branch>]	finish bisection search and go back to branch.
-git bisect visualize            show bisect status in gitk.
-git bisect replay <logfile>	replay bisection log
-git bisect log			show bisect log.'
-    exit 1
-}
-
 bisect_autostart() {
 	test -d "$GIT_DIR/refs/bisect" || {
 		echo >&2 'You need to start by "git bisect start"'
diff --git a/git-branch.sh b/git-branch.sh
index 5306b2719f..0266f46223 100755
--- a/git-branch.sh
+++ b/git-branch.sh
@@ -1,21 +1,12 @@
 #!/bin/sh
 
-GIT_DIR=`git-rev-parse --git-dir` || exit $?
-
-die () {
-    echo >&2 "$*"
-    exit 1
-}
-
-usage () {
-    echo >&2 "usage: $(basename $0)"' [-d <branch>] | [[-f] <branch> [start-point]]
-
-If no arguments, show available branches and mark current branch with a star.
+USAGE='[-d <branch>] | [[-f] <branch> [start-point]]'
+LONG_USAGE='If no arguments, show available branches and mark current branch with a star.
 If one argument, create a new branch <branchname> based off of current HEAD.
-If two arguments, create a new branch <branchname> based off of <start-point>.
-'
-    exit 1
-}
+If two arguments, create a new branch <branchname> based off of <start-point>.'
+
+SUBDIRECTORY_OK='Yes'
+. git-sh-setup
 
 headref=$(git-symbolic-ref HEAD | sed -e 's|^refs/heads/||')
 
diff --git a/git-sh-setup.sh b/git-sh-setup.sh
index b4f10224ba..1e638e493d 100755
--- a/git-sh-setup.sh
+++ b/git-sh-setup.sh
@@ -11,13 +11,37 @@
 # exporting it.
 unset CDPATH
 
-: ${GIT_DIR=.git}
-: ${GIT_OBJECT_DIRECTORY="$GIT_DIR/objects"}
-
 die() {
 	echo >&2 "$@"
 	exit 1
 }
 
-# Make sure we are in a valid repository of a vintage we understand.
-GIT_DIR="$GIT_DIR" git-var GIT_AUTHOR_IDENT >/dev/null || exit
+usage() {
+	die "Usage: $0 $USAGE"
+}
+
+if [ -z "$LONG_USAGE" ]
+then
+	LONG_USAGE="Usage: $0 $USAGE"
+else
+	LONG_USAGE="Usage: $0 $USAGE
+
+$LONG_USAGE"
+fi
+
+case "$1" in
+	--h|--he|--hel|--help)
+	echo "$LONG_USAGE"
+	exit
+esac
+
+if [ -z "$SUBDIRECTORY_OK" ]
+then
+	: ${GIT_DIR=.git}
+	: ${GIT_OBJECT_DIRECTORY="$GIT_DIR/objects"}
+
+	# Make sure we are in a valid repository of a vintage we understand.
+	GIT_DIR="$GIT_DIR" git-var GIT_AUTHOR_IDENT >/dev/null || exit
+else
+	GIT_DIR=$(git-rev-parse --git-dir) || exit
+fi
diff --git a/git-status.sh b/git-status.sh
index 2dda0c505c..50ccd24efb 100755
--- a/git-status.sh
+++ b/git-status.sh
@@ -2,7 +2,16 @@
 #
 # Copyright (c) 2005 Linus Torvalds
 #
-GIT_DIR=$(git-rev-parse --git-dir) || exit
+
+USAGE=''
+SUBDIRECTORY_OK='Yes'
+
+. git-sh-setup
+
+if [ "$#" != "0" ]
+then
+  usage
+fi
 
 report () {
   header="#