[PATCH] Use ‘head -n1’ rather than ‘head -1’

[PATCH] Use ‘head -n1’ rather than ‘head -1’

[Paul Eggert]

POSIX no longer requires support for ‘head -1’.
---
 lib/git-merge-changelog.c | 4 ++--
 tests/test-sigpipe.c      | 2 +-
 tests/test-sigpipe.sh     | 6 +++---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/lib/git-merge-changelog.c b/lib/git-merge-changelog.c
index 679c4aac1a..5708dd5eac 100644
--- a/lib/git-merge-changelog.c
+++ b/lib/git-merge-changelog.c
@@ -1161,9 +1161,9 @@ There is NO WARRANTY, to the extent permitted by law.\n\
     {
       char buf[1000];
       printf ("First line of %%A:\n");
-      sprintf (buf, "head -1 %s", destination_file_name); system (buf);
+      sprintf (buf, "head -n 1 %s", destination_file_name); system (buf);
       printf ("First line of %%B:\n");
-      sprintf (buf, "head -1 %s", other_file_name); system (buf);
+      sprintf (buf, "head -n 1 %s", other_file_name); system (buf);
       printf ("Guessing calling convention: %s\n",
               downstream
               ? "%A = modified by user, %B = upstream"
diff --git a/tests/test-sigpipe.c b/tests/test-sigpipe.c
index 8a02f0c048..ab8745b3bd 100644
--- a/tests/test-sigpipe.c
+++ b/tests/test-sigpipe.c
@@ -46,7 +46,7 @@ main (int argc, char **argv)
     case 'C': signal (SIGPIPE, handler); break;
     }
 
-  /* Produce infinite output.  Since it is piped into "head -1", the writes
+  /* Produce infinite output.  Since it is piped into "head -n 1", the writes
      must ultimately fail.  */
   for (;;)
     {
diff --git a/tests/test-sigpipe.sh b/tests/test-sigpipe.sh
index 5c87f6ed50..a304febf97 100755
--- a/tests/test-sigpipe.sh
+++ b/tests/test-sigpipe.sh
@@ -5,7 +5,7 @@ trap 'rm -fr $tmpfiles' HUP INT QUIT TERM
 
 # Test signal's default behaviour.
 tmpfiles="$tmpfiles t-sigpipeA.tmp"
-${CHECKER} ./test-sigpipe${EXEEXT} A 2> t-sigpipeA.tmp | head -1 > /dev/null
+${CHECKER} ./test-sigpipe${EXEEXT} A 2> t-sigpipeA.tmp | head -n 1 > /dev/null
 if test -s t-sigpipeA.tmp; then
   LC_ALL=C tr -d '\r' < t-sigpipeA.tmp
   rm -fr $tmpfiles; exit 1
@@ -13,7 +13,7 @@ fi
 
 # Test signal's ignored behaviour.
 tmpfiles="$tmpfiles t-sigpipeB.tmp"
-${CHECKER} ./test-sigpipe${EXEEXT} B 2> t-sigpipeB.tmp | head -1 > /dev/null
+${CHECKER} ./test-sigpipe${EXEEXT} B 2> t-sigpipeB.tmp | head -n 1 > /dev/null
 if test -s t-sigpipeB.tmp; then
   LC_ALL=C tr -d '\r' < t-sigpipeB.tmp
   rm -fr $tmpfiles; exit 1
@@ -21,7 +21,7 @@ fi
 
 # Test signal's behaviour when a handler is installed.
 tmpfiles="$tmpfiles t-sigpipeC.tmp"
-${CHECKER} ./test-sigpipe${EXEEXT} C 2> t-sigpipeC.tmp | head -1 > /dev/null
+${CHECKER} ./test-sigpipe${EXEEXT} C 2> t-sigpipeC.tmp | head -n 1 > /dev/null
 if test -s t-sigpipeC.tmp; then
   LC_ALL=C tr -d '\r' < t-sigpipeC.tmp
   rm -fr $tmpfiles; exit 1
-- 
2.39.0

Re: [PATCH] Use ‘head -n1’ rather than ‘head -1’

[Bruno Haible]

> POSIX no longer requires support for ‘head -1’.

Thanks. I'm adding a ChangeLog entry for this change:


2023-01-16  Paul Eggert  <eggert@cs.ucla.edu>

	sigpipe tests: Modernize use of 'head'.
	POSIX no longer requires support for ‘head -1’.
	* tests/test-sigpipe.sh: Use ‘head -n1’ rather than ‘head -1’.
	* tests/test-sigpipe.c (main): Likewise.
	* lib/git-merge-changelog.c (main): Update comment accordingly.