remove use of "tail -n 1" and "tail -1"

The "-n" syntax is not supported by System V versions of
tail (which prefer "tail -1"). Unfortunately "tail -1" is
not actually POSIX.  We had some of both forms in our
scripts.

Since neither form works everywhere, this patch replaces
both with the equivalent sed invocation:

  sed -ne '$p'

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-am.sh

@@ -357,7 +357,7 @@ do
 		LAST_SIGNED_OFF_BY=`
 		    sed -ne '/^Signed-off-by: /p' \
 		    "$dotest/msg-clean" |
-		    tail -n 1
+		    sed -ne '$p'
 		`
 		ADD_SIGNOFF=`
 		    test "$LAST_SIGNED_OFF_BY" = "$SIGNOFF" || {

git-rebase--interactive.sh

@@ -218,7 +218,7 @@ nth_string () {
 make_squash_message () {
 	if test -f "$SQUASH_MSG"; then
 		COUNT=$(($(sed -n "s/^# This is [^0-9]*\([1-9][0-9]*\).*/\1/p" \
-			< "$SQUASH_MSG" | tail -n 1)+1))
+			< "$SQUASH_MSG" | sed -ne '$p')+1))
 		echo "# This is a combination of $COUNT commits."
 		sed -e 1d -e '2,/^./{
 			/^$/d

t/t3404-rebase-interactive.sh

@@ -122,8 +122,8 @@ test_expect_success 'reflog for the branch shows state before rebase' '
 
 test_expect_success 'exchange two commits' '
 	FAKE_LINES="2 1" git rebase -i HEAD~2 &&
-	test H = $(git cat-file commit HEAD^ | tail -n 1) &&
-	test G = $(git cat-file commit HEAD | tail -n 1)
+	test H = $(git cat-file commit HEAD^ | sed -ne \$p) &&
+	test G = $(git cat-file commit HEAD | sed -ne \$p)
 '
 
 cat > expect << EOF

t/t5302-pack-index.sh

@@ -103,7 +103,7 @@ test_expect_success \
 test_expect_success \
     '[index v1] 2) create a stealth corruption in a delta base reference' \
     '# this test assumes a delta smaller than 16 bytes at the end of the pack
-     git show-index <1.idx | sort -n | tail -n 1 | (
+     git show-index <1.idx | sort -n | sed -ne \$p | (
        read delta_offs delta_sha1 &&
        git cat-file blob "$delta_sha1" > blob_1 &&
        chmod +w ".git/objects/pack/pack-${pack1}.pack" &&
@@ -141,7 +141,7 @@ test_expect_success \
 test_expect_success \
     '[index v2] 2) create a stealth corruption in a delta base reference' \
     '# this test assumes a delta smaller than 16 bytes at the end of the pack
-     git show-index <1.idx | sort -n | tail -n 1 | (
+     git show-index <1.idx | sort -n | sed -ne \$p | (
        read delta_offs delta_sha1 delta_crc &&
        git cat-file blob "$delta_sha1" > blob_3 &&
        chmod +w ".git/objects/pack/pack-${pack1}.pack" &&

t/t6030-bisect-porcelain.sh

@@ -219,7 +219,7 @@ test_expect_success 'bisect run & skip: cannot tell between 2' '
 	add_line_into_file "6: Yet a line." hello &&
 	HASH6=$(git rev-parse --verify HEAD) &&
 	echo "#"\!"/bin/sh" > test_script.sh &&
-	echo "tail -1 hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
+	echo "sed -ne \\\$p hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
 	echo "grep line hello > /dev/null" >> test_script.sh &&
 	echo "test \$? -ne 0" >> test_script.sh &&
 	chmod +x test_script.sh &&
@@ -244,8 +244,8 @@ test_expect_success 'bisect run & skip: find first bad' '
 	add_line_into_file "7: Should be the last line." hello &&
 	HASH7=$(git rev-parse --verify HEAD) &&
 	echo "#"\!"/bin/sh" > test_script.sh &&
-	echo "tail -1 hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
-	echo "tail -1 hello | grep day > /dev/null && exit 125" >> test_script.sh &&
+	echo "sed -ne \\\$p hello | grep Ciao > /dev/null && exit 125" >> test_script.sh &&
+	echo "sed -ne \\\$p hello | grep day > /dev/null && exit 125" >> test_script.sh &&
 	echo "grep Yet hello > /dev/null" >> test_script.sh &&
 	echo "test \$? -ne 0" >> test_script.sh &&
 	chmod +x test_script.sh &&

t/t7600-merge.sh

@@ -165,7 +165,7 @@ verify_mergeheads() {
 	fi &&
 	while test $# -gt 0
 	do
-		head=$(head -n $i .git/MERGE_HEAD | tail -n 1)
+		head=$(head -n $i .git/MERGE_HEAD | sed -ne \$p)
 		if test "$1" != "$head"
 		then
 			echo "[OOPS] MERGE_HEAD $i != $1"

t/t9400-git-cvsserver-server.sh

@@ -54,7 +54,7 @@ test_expect_success 'setup' '
 test_expect_success 'basic checkout' \
   'GIT_CONFIG="$git_config" cvs -Q co -d cvswork master &&
    test "$(echo $(grep -v ^D cvswork/CVS/Entries|cut -d/ -f2,3,5 | head -n 1))" = "empty/1.1/"
-   test "$(echo $(grep -v ^D cvswork/CVS/Entries|cut -d/ -f2,3,5 | tail -n 1))" = "secondrootfile/1.1/"'
+   test "$(echo $(grep -v ^D cvswork/CVS/Entries|cut -d/ -f2,3,5 | sed -ne \$p))" = "secondrootfile/1.1/"'
 
 #------------------------
 # PSERVER AUTHENTICATION
@@ -94,7 +94,7 @@ EOF
 
 test_expect_success 'pserver authentication' \
   'cat request-anonymous | git-cvsserver pserver >log 2>&1 &&
-   tail -n1 log | grep "^I LOVE YOU$"'
+   sed -ne \$p log | grep "^I LOVE YOU$"'
 
 test_expect_success 'pserver authentication failure (non-anonymous user)' \
   'if cat request-git | git-cvsserver pserver >log 2>&1
@@ -103,11 +103,11 @@ test_expect_success 'pserver authentication failure (non-anonymous user)' \
    else
        true
    fi &&
-   tail -n1 log | grep "^I HATE YOU$"'
+   sed -ne \$p log | grep "^I HATE YOU$"'
 
 test_expect_success 'pserver authentication (login)' \
   'cat login-anonymous | git-cvsserver pserver >log 2>&1 &&
-   tail -n1 log | grep "^I LOVE YOU$"'
+   sed -ne \$p log | grep "^I LOVE YOU$"'
 
 test_expect_success 'pserver authentication failure (login/non-anonymous user)' \
   'if cat login-git | git-cvsserver pserver >log 2>&1
@@ -116,7 +116,7 @@ test_expect_success 'pserver authentication failure (login/non-anonymous user)'
    else
        true
    fi &&
-   tail -n1 log | grep "^I HATE YOU$"'
+   sed -ne \$p log | grep "^I HATE YOU$"'
 
 
 # misuse pserver authentication for testing of req_Root
@@ -154,7 +154,7 @@ test_expect_success 'req_Root failure (conflicting roots)' \
 
 test_expect_success 'req_Root (strict paths)' \
   'cat request-anonymous | git-cvsserver --strict-paths pserver $SERVERDIR >log 2>&1 &&
-   tail -n1 log | grep "^I LOVE YOU$"'
+   sed -ne \$p log | grep "^I LOVE YOU$"'
 
 test_expect_success 'req_Root failure (strict-paths)' '
     ! cat request-anonymous |
@@ -163,7 +163,7 @@ test_expect_success 'req_Root failure (strict-paths)' '
 
 test_expect_success 'req_Root (w/o strict-paths)' \
   'cat request-anonymous | git-cvsserver pserver $WORKDIR/ >log 2>&1 &&
-   tail -n1 log | grep "^I LOVE YOU$"'
+   sed -ne \$p log | grep "^I LOVE YOU$"'
 
 test_expect_success 'req_Root failure (w/o strict-paths)' '
     ! cat request-anonymous |
@@ -181,7 +181,7 @@ EOF
 
 test_expect_success 'req_Root (base-path)' \
   'cat request-base | git-cvsserver --strict-paths --base-path $WORKDIR/ pserver $SERVERDIR >log 2>&1 &&
-   tail -n1 log | grep "^I LOVE YOU$"'
+   sed -ne \$p log | grep "^I LOVE YOU$"'
 
 test_expect_success 'req_Root failure (base-path)' '
     ! cat request-anonymous |
@@ -192,14 +192,14 @@ GIT_DIR="$SERVERDIR" git config --bool gitcvs.enabled false || exit 1
 
 test_expect_success 'req_Root (export-all)' \
   'cat request-anonymous | git-cvsserver --export-all pserver $WORKDIR >log 2>&1 &&
-   tail -n1 log | grep "^I LOVE YOU$"'
+   sed -ne \$p log | grep "^I LOVE YOU$"'
 
 test_expect_success 'req_Root failure (export-all w/o whitelist)' \
   '! (cat request-anonymous | git-cvsserver --export-all pserver >log 2>&1 || false)'
 
 test_expect_success 'req_Root (everything together)' \
   'cat request-base | git-cvsserver --export-all --strict-paths --base-path $WORKDIR/ pserver $SERVERDIR >log 2>&1 &&
-   tail -n1 log | grep "^I LOVE YOU$"'
+   sed -ne \$p log | grep "^I LOVE YOU$"'
 
 GIT_DIR="$SERVERDIR" git config --bool gitcvs.enabled true || exit 1