Thanks for looking into and fixing that. One quibble: those long comments are
probably more trouble than they're worth. I found that they got in the way of my
understanding the code, as my eyes glazed over when reading them. And when I
finally forced myself to read one, I found that at least one important detail
was missing: the "#! -*-perl-*-" line is not just there for Emacs, but is also
there for Perl.
Instead of adding even more length to a comment that is already a bit of an
obstacle to understanding the code, I suggest we just cite perlrun's man page as
in the attached proposed patch. This should be good enough for anyone who's not
already versed in perl+sh.
>From 7969fe73da89ac372c681dca7839b880b59767f1 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Sat, 15 Jun 2019 11:27:52 -0700
Subject: [PATCH] Use shorter perlrun comment
* build-aux/announce-gen, build-aux/gitlog-to-changelog:
* build-aux/prefix-gnulib-mk, build-aux/update-copyright:
* build-aux/useless-if-before-free, tests/test-update-copyright.sh:
Just cite perlrun(1) in the comment.
---
ChangeLog | 8 ++++++++
build-aux/announce-gen | 13 +------------
build-aux/gitlog-to-changelog | 13 +------------
build-aux/prefix-gnulib-mk | 13 +------------
build-aux/update-copyright | 13 +------------
build-aux/useless-if-before-free | 13 +------------
tests/test-update-copyright.sh | 13 +------------
7 files changed, 14 insertions(+), 72 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index a0d2f415f..77e66c0e9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2019-06-15 Paul Eggert <egg...@cs.ucla.edu>
+
+ Use shorter perlrun comment
+ * build-aux/announce-gen, build-aux/gitlog-to-changelog:
+ * build-aux/prefix-gnulib-mk, build-aux/update-copyright:
+ * build-aux/useless-if-before-free, tests/test-update-copyright.sh:
+ Just cite perlrun(1) in the comment.
+
2019-06-15 Bruno Haible <br...@clisp.org>
Fix scripts to have valid executable format on Alpine Linux.
diff --git a/build-aux/announce-gen b/build-aux/announce-gen
index b5728338c..1e2648d0e 100755
--- a/build-aux/announce-gen
+++ b/build-aux/announce-gen
@@ -1,17 +1,6 @@
#!/bin/sh
#! -*-perl-*-
-# This is a prologue that allows to run a perl script as an executable
-# on systems that are compliant to a POSIX version before POSIX:2017.
-# On such systems, the usual invocation of an executable through execlp()
-# or execvp() fails with ENOEXEC if it is a script that does not start
-# with a #! line. The script interpreter mentioned in the #! line has
-# to be /bin/sh, because on GuixSD systems that is the only program that
-# has a fixed file name. The second line is for editing this file in
-# Emacs. The next two lines below are valid code in both sh and perl.
-# When executed by sh, they re-execute the script through the perl
-# program found in $PATH. The '-x' option is essential; without it,
-# perl would re-execute the script through /bin/sh. When executed by
-# perl, the next two lines are a no-op.
+# Either perl or sh can run this file; see perlrun(1).
eval 'exec perl -wSx "$0" "$@"'
if 0;
diff --git a/build-aux/gitlog-to-changelog b/build-aux/gitlog-to-changelog
index a616b8234..68722bacb 100755
--- a/build-aux/gitlog-to-changelog
+++ b/build-aux/gitlog-to-changelog
@@ -1,17 +1,6 @@
#!/bin/sh
#! -*-perl-*-
-# This is a prologue that allows to run a perl script as an executable
-# on systems that are compliant to a POSIX version before POSIX:2017.
-# On such systems, the usual invocation of an executable through execlp()
-# or execvp() fails with ENOEXEC if it is a script that does not start
-# with a #! line. The script interpreter mentioned in the #! line has
-# to be /bin/sh, because on GuixSD systems that is the only program that
-# has a fixed file name. The second line is for editing this file in
-# Emacs. The next two lines below are valid code in both sh and perl.
-# When executed by sh, they re-execute the script through the perl
-# program found in $PATH. The '-x' option is essential; without it,
-# perl would re-execute the script through /bin/sh. When executed by
-# perl, the next two lines are a no-op.
+# Either perl or sh can run this file; see perlrun(1).
eval 'exec perl -wSx "$0" "$@"'
if 0;
diff --git a/build-aux/prefix-gnulib-mk b/build-aux/prefix-gnulib-mk
index 66e138b46..10871a286 100755
--- a/build-aux/prefix-gnulib-mk
+++ b/build-aux/prefix-gnulib-mk
@@ -1,17 +1,6 @@
#!/bin/sh
#! -*-perl-*-
-# This is a prologue that allows to run a perl script as an executable
-# on systems that are compliant to a POSIX version before POSIX:2017.
-# On such systems, the usual invocation of an executable through execlp()
-# or execvp() fails with ENOEXEC if it is a script that does not start
-# with a #! line. The script interpreter mentioned in the #! line has
-# to be /bin/sh, because on GuixSD systems that is the only program that
-# has a fixed file name. The second line is for editing this file in
-# Emacs. The next two lines below are valid code in both sh and perl.
-# When executed by sh, they re-execute the script through the perl
-# program found in $PATH. The '-x' option is essential; without it,
-# perl would re-execute the script through /bin/sh. When executed by
-# perl, the next two lines are a no-op.
+# Either perl or sh can run this file; see perlrun(1).
eval 'exec perl -wSx "$0" "$@"'
if 0;
diff --git a/build-aux/update-copyright b/build-aux/update-copyright
index fa9d427e9..445c9cb06 100755
--- a/build-aux/update-copyright
+++ b/build-aux/update-copyright
@@ -1,17 +1,6 @@
#!/bin/sh
#! -*-perl-*-
-# This is a prologue that allows to run a perl script as an executable
-# on systems that are compliant to a POSIX version before POSIX:2017.
-# On such systems, the usual invocation of an executable through execlp()
-# or execvp() fails with ENOEXEC if it is a script that does not start
-# with a #! line. The script interpreter mentioned in the #! line has
-# to be /bin/sh, because on GuixSD systems that is the only program that
-# has a fixed file name. The second line is for editing this file in
-# Emacs. The next two lines below are valid code in both sh and perl.
-# When executed by sh, they re-execute the script through the perl
-# program found in $PATH. The '-x' option is essential; without it,
-# perl would re-execute the script through /bin/sh. When executed by
-# perl, the next two lines are a no-op.
+# Either perl or sh can run this file; see perlrun(1).
eval 'exec perl -wSx "$0" "$@"'
if 0;
diff --git a/build-aux/useless-if-before-free b/build-aux/useless-if-before-free
index 0701e7b20..36ff86409 100755
--- a/build-aux/useless-if-before-free
+++ b/build-aux/useless-if-before-free
@@ -1,17 +1,6 @@
#!/bin/sh
#! -*-perl-*-
-# This is a prologue that allows to run a perl script as an executable
-# on systems that are compliant to a POSIX version before POSIX:2017.
-# On such systems, the usual invocation of an executable through execlp()
-# or execvp() fails with ENOEXEC if it is a script that does not start
-# with a #! line. The script interpreter mentioned in the #! line has
-# to be /bin/sh, because on GuixSD systems that is the only program that
-# has a fixed file name. The second line is for editing this file in
-# Emacs. The next two lines below are valid code in both sh and perl.
-# When executed by sh, they re-execute the script through the perl
-# program found in $PATH. The '-x' option is essential; without it,
-# perl would re-execute the script through /bin/sh. When executed by
-# perl, the next two lines are a no-op.
+# Either perl or sh can run this file; see perlrun(1).
eval 'exec perl -wSx "$0" "$@"'
if 0;
diff --git a/tests/test-update-copyright.sh b/tests/test-update-copyright.sh
index 9ef5344ea..30e7090b7 100755
--- a/tests/test-update-copyright.sh
+++ b/tests/test-update-copyright.sh
@@ -39,18 +39,7 @@ s=$TMP-script
cat <<\EOF > $s
#!/bin/sh
#! -*-perl-*-
-# This is a prologue that allows to run a perl script as an executable
-# on systems that are compliant to a POSIX version before POSIX:2017.
-# On such systems, the usual invocation of an executable through execlp()
-# or execvp() fails with ENOEXEC if it is a script that does not start
-# with a #! line. The script interpreter mentioned in the #! line has
-# to be /bin/sh, because on GuixSD systems that is the only program that
-# has a fixed file name. The second line is for editing this file in
-# Emacs. The next two lines below are valid code in both sh and perl.
-# When executed by sh, they re-execute the script through the perl
-# program found in $PATH. The '-x' option is essential; without it,
-# perl would re-execute the script through /bin/sh. When executed by
-# perl, the next two lines are a no-op.
+# Either perl or sh can run this file; see perlrun(1).
eval 'exec perl -wSx "$0" "$@"'
if 0;
--
2.21.0
