wrapper

#!/bin/bash -x

# Wrapper to run executable that begins with $1
# Useful, for example, to find and run a suitable python2 executable
# $1 must be either --file=/path/to/caller when the caller is a file
# (to exclude itself from the search) or the desired target name
# (for alias, functions, etc)
#
# Example: wrapper --file="$0" "$@"
#          wrapper "python2"   "$@"

case "$1" in
	--file=*)
		caller=${1#*=}
		name=${caller##*/}
	;;
	*)
		caller=""
		name=$1
	;;
esac

[[ "$name" && (-z "$caller" || -f "$caller") ]] || {
	echo "Usage: [--file=CALLER | TARGET] [target options]" >&2
	exit 1
}

IFS=:
for path in $PATH; do
	for file in "$path"/"$name"*; do
		[[ -x "$file" && ! ("$caller" && "$file" -ef "$caller") ]] && {
			shift
			echo exec "$file" "$@"
			exit
		}
	done
done

echo "No executable named ${name}* was found" >&2
exit 1

# neater version for the loops (by geirha. a bit strict on exec names)
#while read -r file ; do : ; done < <(type -ap python2{,.{9..0}})

# original version of the test (3x slower, but catches copies of $0 on $PATH)
#[[ -x "$file" ]] && ! cmp --silent "$0" "$file" && :