Hi Jim, > >> But on your system, it exits with status 2. > > > > Yes: > > > > $ ./gunzip --help > /dev/full > > echo: No space left on device > > $ echo $? > > 2 > > Ohh... > So it's the HP-UX shell's "echo" that is detecting the write failure > but setting errno to 2 rather than the 1
'bash' on the same system behaves the same way: $ bash gunzip --help > /dev/full echo: No space left on device $ echo $? 2 And that is despite of $ bash -c 'type echo' echo is a shell builtin $ bash -c 'echo foo > /dev/full' bash: line 0: echo: write error: No space left on device $ echo $? 1 $ bash -c '/usr/bin/echo foo > /dev/full' /usr/bin/echo: No space left on device $ echo $? 2 It looks like the 'gunzip' script is never using the bash built-in but always the 'echo' in $PATH. Probably because of 'exec echo ...'. This patch: *** gunzip.orig Sat Nov 11 20:05:54 2017 --- gunzip Sun Nov 12 22:38:15 2017 *************** *** 50,57 **** Report bugs to <bug-gzip@gnu.org>." case $1 in ! --help) exec echo "$usage";; ! --version) exec echo "$version";; esac exec gzip -d "$@" --- 50,57 ---- Report bugs to <bug-gzip@gnu.org>." case $1 in ! --help) echo "$usage" || exit 1; exit 0;; ! --version) echo "$version" || exit 1; exit 0;; esac exec gzip -d "$@" works fine with bash but not with /bin/sh: $ bash gunzip --help > /dev/full gunzip: line 53: echo: write error: No space left on device $ echo $? 1 $ ./gunzip --help > /dev/full $ echo $? 0 But this one works with both: *** gunzip.orig Sat Nov 11 20:05:54 2017 --- gunzip Sun Nov 12 22:46:39 2017 *************** *** 50,57 **** Report bugs to <bug-gzip@gnu.org>." case $1 in ! --help) exec echo "$usage";; ! --version) exec echo "$version";; esac exec gzip -d "$@" --- 50,62 ---- Report bugs to <bug-gzip@gnu.org>." case $1 in ! # Produce output and exit with code 1 if there is a write error. ! # Use 'exec echo', not plain 'echo', because the 'echo' built-in in ! # HP-UX /bin/sh does not check for write errors. ! # Use '|| exit 1', because the 'echo' program on HP-UX exits with ! # code 2 in case of a write error, but we want code 1. ! --help) (exec echo "$usage") || exit 1; exit 0;; ! --version) (exec echo "$version") || exit 1; exit 0;; esac exec gzip -d "$@" $ bash gunzip --help > /dev/full echo: No space left on device $ echo $? 1 $ ./gunzip --help > /dev/full echo: No space left on device $ echo $? 1
