[PATCH 1/2] gcore: improve shell use

[Sam James <sam@gentoo.org>]

* Use bash tests, i.e. '[[' and ']]', instead of POSIX '[' and ']' or
  'test' which have their own pitfalls, given gcore has a bash shebang already.

* Use $() subshell syntax rather than `backticks`.
---
 gdb/gcore-1.in | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/gdb/gcore-1.in b/gdb/gcore-1.in
index c0979a51db3..edd807b86dc 100644
--- a/gdb/gcore-1.in
+++ b/gdb/gcore-1.in
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-#   Copyright (C) 2003-2024 Free Software Foundation, Inc.
+#   Copyright (C) 2003-2025 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -64,7 +64,7 @@ function print_version() {
 }
 
 while getopts vhao:d:-: OPT; do
-    if [ "$OPT" = "-" ]; then
+    if [[ "$OPT" = "-" ]]; then
 	OPT="${OPTARG%%=*}"
 	OPTARG="${OPTARG#'$OPT'}"
 	OPTARG="${OPTARG#=}"
@@ -111,7 +111,7 @@ done
 
 shift $((OPTIND-1))
 
-if [ "$#" -eq "0" ]
+if [[ "$#" -eq "0" ]]
 then
     print_usage 1>&2
     exit 1
@@ -119,19 +119,19 @@ fi
 
 # Attempt to fetch the absolute path to the gcore script that was
 # called.
-binary_path=`dirname "$0"`
+binary_path=$(dirname "$0")
 
-if test "x$binary_path" = x. ; then
+if [[ $binary_path == x. ]] ; then
   # We got "." back as a path.  This means the user executed
   # the gcore script locally (i.e. ./gcore) or called the
   # script via a shell interpreter (i.e. sh gcore).
-  binary_basename=`basename "$0"`
+  binary_basename=$(basename "$0")
 
   # If the gcore script was called like "sh gcore" and the script
   # lives in the current directory, "which" will not give us "gcore".
   # So first we check if the script is in the current directory
   # before using the output of "which".
-  if test -f "$binary_basename" ; then
+  if [[ -f "$binary_basename" ]]; then
     # We have a local gcore script in ".".  This covers the case of
     # doing "./gcore" or "sh gcore".
     binary_path="."
@@ -139,14 +139,14 @@ if test "x$binary_path" = x. ; then
     # The gcore script was not found in ".", which means the script
     # was called from somewhere else in $PATH by "sh gcore".
     # Extract the correct path now.
-    binary_path_from_env=`which "$0"`
-    binary_path=`dirname "$binary_path_from_env"`
+    binary_path_from_env=$(which "$0")
+    binary_path=$(dirname "$binary_path_from_env")
   fi
 fi
 
 # Check if the GDB binary is in the expected path.  If not, just
 # quit with a message.
-if [ ! -f "$binary_path/@GDB_TRANSFORM_NAME@" ]; then
+if [[ ! -f "$binary_path/@GDB_TRANSFORM_NAME@" ]]; then
   echo "gcore: GDB binary (${binary_path}/@GDB_TRANSFORM_NAME@) not found"
   exit 1
 fi
@@ -166,7 +166,7 @@ do
 	    "${dump_all_cmds[@]}" \
 	    -ex "attach $pid" -ex "gcore $prefix.$pid" -ex detach -ex quit
 
-	if [ -r "$prefix.$pid" ] ; then
+	if [[ -r "$prefix.$pid" ]] ; then
 	    rc=0
 	else
 	    echo "@GCORE_TRANSFORM_NAME@: failed to create $prefix.$pid"
-- 
2.49.0