16.7 ls Shortcuts: ll, lf, lg, etc.

The old 4.1BSD UNIX system I worked on in the early 1980s had commands named ll , for ls -l ; lf , for ls -F ; and lm , for the (defunct, on BSD at least... RIP) ls -m command. [For those of us who don't remember it, ls -m listed files separated by commas, rather than spaces. -ML  ] When they left my system, I made my own shell script to do the same things. If your system doesn't have these, you can install the script from the CD-ROM.

This is the single script file for all the commands:

#! /bin/sh
case $0 in
*lf)  exec ls -F "$@";;
*lg)  exec ls -lg "$@";;
*ll)  exec ls -l "$@";;
*lm)  ls "$@" |
      awk '{
        if ((length($0) + 2 + length(inline)) > 79) {
            print inline ","
            inline = $0
        }
        else if (length(inline) != 0)
            inline = inline ", " $0
        else # this is the first filename
            inline = $0
      }
      END {
        print inline
      }'
      ;;
*lr)  exec ls -lR "$@";;
*)    echo "$0: Help!  Shouldn't get here!" 1>&2; exit 1;;
esac

The exec ( 45.7 ) command saves a process - this was important on my overloaded VAX 11/750, and doesn't hurt on faster systems.

You can install this script from the CD-ROM or just type it in. If you type it into a file named lf , don't forget to make the four other links ( 18.5 ) : lg , ll , lm , and lr . The script tests the name it was called with, in $0 , to decide which ls command to run. This trick saves disk space.

System V still has the -m option, so you can replace the *lm) section with plain ls -m . Also, on some UNIXes, the ls -g option does nothing; replace that section with ls -lG or ls -lo . You can add other commands, too, by adding a line to the case and another link. (For more on shell programming, start with article 44.1 .)