hooks--pre-push.sample: modernize script

The preferred form for a command substitution is $() over ``. Use this
form for the command substitution in the sample hook.

The preferred form for conditional tests is to use `test` over [].
Replace [] with `test`.

Finally, replace all instances of "sha" with "oid".

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

templates/hooks--pre-push.sample

@@ -14,7 +14,7 @@
 # Information about the commits which are being pushed is supplied as lines to
 # the standard input in the form:
 #
-#   <local ref> <local sha1> <remote ref> <remote sha1>
+#   <local ref> <local oid> <remote ref> <remote oid>
 #
 # This sample shows how to prevent push of commits where the log message starts
 # with "WIP" (work in progress).
@@ -24,25 +24,25 @@ url="$2"
 
 z40=0000000000000000000000000000000000000000
 
-while read local_ref local_sha remote_ref remote_sha
+while read local_ref local_oid remote_ref remote_oid
 do
-	if [ "$local_sha" = $z40 ]
+	if test "$local_oid" = $z40
 	then
 		# Handle delete
 		:
 	else
-		if [ "$remote_sha" = $z40 ]
+		if test "$remote_oid" = $z40
 		then
 			# New branch, examine all commits
-			range="$local_sha"
+			range="$local_oid"
 		else
 			# Update to existing branch, examine new commits
-			range="$remote_sha..$local_sha"
+			range="$remote_oid..$local_oid"
 		fi
 
 		# Check for WIP commit
-		commit=`git rev-list -n 1 --grep '^WIP' "$range"`
-		if [ -n "$commit" ]
+		commit=$(git rev-list -n 1 --grep '^WIP' "$range")
+		if test -n "$commit"
 		then
 			echo >&2 "Found WIP commit in $local_ref, not pushing"
 			exit 1