[PATCH 2/3] gcore: add -h|--help options, and improve help/usage message output

Andrew Burgess
2025-03-06T17:14:12Z

Like the previous commit, this copies a lot from:

commit fb2ded33c1e519659743047ed7817166545b6d91
Date: Fri Dec 20 12:46:11 2024 -0800

Add gstack script

And adds -h | --help options to the gcore script, and smartens up the
help and usage output messages.

The usage text is now split over several lines (as it was getting a
bit long), and an input error suggests using `--help` instead of
printing the full usage string.

These changes bring gcore and gstack closer in behaviour.
---
gdb/NEWS | 3 ++-
gdb/doc/gdb.texinfo | 6 +++++-
gdb/gcore-1.in | 50 ++++++++++++++++++++++++++++++++++++++++-----
3 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/gdb/NEWS b/gdb/NEWS
index d4453914755..5d9d9fb3063 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -27,7 +27,8 @@
* Linux checkpoint code has been updated to work with multiple inferiors.

* The gcore script now has a -v or --version option, which prints the
- version number, and then exits.
+ version number, and then exits. As well as a -h or --help option,
+ which prints each options and a brief description.

* New commands

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 1ab87dd37f9..a1ae45c5121 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -51386,7 +51386,7 @@ gcore man

@format
@c man begin SYNOPSIS gcore
-gcore [-v | --version] [-a] [-o @var{prefix}] [-d @var{directory}]
+gcore [-v | --version] [-h | --help] [-a] [-o @var{prefix}] [-d @var{directory}]
@var{pid1} [@var{pid2}...@var{pidN}]
@c man end
@end format
@@ -51420,6 +51420,10 @@ gcore man
Use @var{directory} as the data directory when invoking @value{GDBN} for running
the gcore command. This argument is optional.

+@item --help
+@itemx -h
+List all options, with brief explanations.
+
@item --version
@itemx -v
Print version information and then exit.
diff --git a/gdb/gcore-1.in b/gdb/gcore-1.in
index ce2f7321148..129e3697fb7 100644
--- a/gdb/gcore-1.in
+++ b/gdb/gcore-1.in
@@ -32,11 +32,38 @@ dump_all_cmds=()

data_directory_opt=()

+function print_usage() {
+ prefix="Usage: $0"
+ paddin=$(printf '%*s' ${#prefix})
+
+ echo "$prefix [-h|--help] [-v|--version]"
+ echo "$paddin [-a] [-o prefix] [-d data-directory]"
+ echo "$paddin pid1 [pid2...pidN]"
+}
+
+function print_try_help() {
+ echo "Try '$0 --help' for more information."
+}
+
+function print_help() {
+ print_usage
+ echo
+ echo "Create a core file of a running program using GDB."
+ echo
+ echo " -h, --help Print this message then exit."
+ echo " -v, --version Print version information then exit."
+ echo " -a Dump all memory mappings."
+ echo " -o prefix Use 'prefix.pid' as the core file name."
+ echo " The default prefix is 'core'."
+ echo " -d dir Pass '--data-directory dir' as an argument"
+ echo " to GDB."
+}
+
function print_version() {
echo "GNU gcore (${PKGVERSION}) ${VERSION}"
}

-while getopts :vao:d:-: OPT; do
+while getopts vhao:d:-: OPT; do
if [ "$OPT" = "-" ]; then
OPT="${OPTARG%%=*}"
OPTARG="${OPTARG#'$OPT'}"
@@ -58,13 +85,26 @@ while getopts :vao:d:-: OPT; do
d)
data_directory_opt=("--data-directory" "$OPTARG")
;;
+ h | help)
+ print_help
+ exit 0
+ ;;
v | version)
print_version
exit 0
;;
+ \?)
+ # getopts has already output an error message.
+ print_try_help 1>&2
+ exit 2
+ ;;
*)
- echo "usage: @GCORE_TRANSFORM_NAME@ [-v | --version] [-a] [-o prefix] [-d data-directory] pid1 [pid2...pidN]"
- exit 2
+ # Unknown single character options are handled by the \?
+ # case above. This is formatted to match the error
+ # getopts gives for an unknown single character option.
+ echo "$0: illegal option -- $OPT" 1>&2
+ print_try_help 1>&2
+ exit 2
;;
esac
done
@@ -73,8 +113,8 @@ shift $((OPTIND-1))

if [ "$#" -eq "0" ]
then
- echo "usage: @GCORE_TRANSFORM_NAME@ [-a] [-o prefix] [-d data-directory] pid1 [pid2...pidN]"
- exit 2
+ print_usage 1>&2
+ exit 1
fi

# Attempt to fetch the absolute path to the gcore script that was
--
2.47.1