l: propagate exit status from ls

Previously the exit status from this script was
that of the final sed(1), which is usually success,
even if specified files can't be found etc.

Instead use the exit code from the wrapped ls command.

`set -o pipefail` would be an elegant way to achieve that,
but that's bash/ksh/zsh specific, so we manually setup
file descriptors so that the exit status from ls can
be manually output and captured.

Author: pixelb

scripts/l

@@ -14,7 +14,7 @@
 #                       Don't error for ls without --group-dir or --no-group
 #    V0.3, 21 Oct 2009, Handle older ls' which pepper output with reset codes
 #
-#    V1.1, 05 Jun 2014
+#    V1.2, 12 Oct 2016
 #      http://github.com/pixelb/scripts/commits/master/scripts/l
 
 # apply thousands separator to file sizes
@@ -138,9 +138,17 @@ $ls --no-group -d . >/dev/null 2>&1 && ng=--no-group
 lfmt=lfmt
 echo "$*" | grep -E -- "-(m|i|x|s|C|-version|-help)" >/dev/null && lfmt=""
 
+# set -o pipefail is bash/ksh/zsh specific
+# So manually propagate the exit status from ls.
+# See http://stackoverflow.com/a/30658405/4421
+
+exec 4>&1
+ls_status=`{ {
+
 # Start with the standard long format listing
 # with colours, and latest files at bottom
-$ls -lrtq $color_opt$color_when $ng $gdf "$@" |
+$ls -lrtq $color_opt$color_when $ng $gdf "$@";
+printf $? 1>&3; } |
 
 # process with sed to...
 sed "
@@ -181,4 +189,13 @@ sed "
 
   # restore any reset codes replaced above
   s/^0/${ESC}[0m/
-"
+" 1>&4; } 3>&1`
+
+sed_status=$?
+
+# Note if sed fails, then if ls outputs it will usually get
+# a SIGPIPE and exit with status 141.  Though that's dependent
+# on ls(1) propagating that "error", and also will not be the case
+# if ls does not output after sed terminates.  So factor both
+# exit values into the final exit status.
+test $ls_status != 0 && exit $ls_status || exit $sed_status