Chapter 10. Korn Shell Administration

Many installations have done this with absolutely no ill effects. Not only does this make the Korn shell your system's standard login shell, but it also makes most existing Bourne shell scripts run faster, and it has security advantages that we'll see later in this chapter.

dirs=$(print -- $PATH |
	sed -e 's/^:/.:/' -e 's/::/:.:/' -e s'/:$/:./' -e 's/:/ /g')
for d in $dirs
do
	print "checking $d:"
	cd "$d"
	scripts=$(file * | grep 'shell script' | cut -d: -f1)
	grep -l '\^' $scripts /dev/null
done

The first statement of this script pulls $PATH apart into separate directories, including handling the several cases of empty separators which signify the current directory. The sed(1) program is a stream editor that performs editing operations on its input, and prints the changed contents on its output. The result is assigned to dirs, which is then used as the item list in the for loop. For each directory, it cds there and finds all shell scripts by piping the file command into grep and then, to extract the filename only, into cut. Then it searches each script for the ^ character. The -l option to grep simply lists all filenames that match the pattern, without printing the matching lines. The grep command has /dev/null on the end of the list of files in case $scripts happens to be empty. If you're adventurous, you could do all the work on one line:

grep -l '\^' $(file * | grep 'shell script' | cut -d: -f1) /dev/null