35.7 offset: Indent Text

Do you have a printer that starts each line too close to the left margin? You might want to indent text to make it look better on the screen or a printed page. Here's a shell script that does that. It reads from files or standard input and writes to standard output. The default indentation is 5 spaces. For example, to send a copy of a file named graph to the lp printer, indented 12 spaces:

% 

offset -12 graph | lp

There are easier ways to do this (with awk ( 33.11 ) , for instance). This script uses the Bourne shell case statement in an interesting way though, and that might give you ideas for other work.

#! /bin/sh  # GET INDENTATION (IF ANY) AND CHECK FOR BOGUS NUMBERS: case "$1" in -[0-9]|-[0-9][0-9]) indent="$1"; shift ;; -*) echo "`basename $0`: '$1' isn't -number or is > 99." 1>&2; exit 1 ;; esac  # SET DEFAULT: case "$indent" in "") indent=-5 ;; esac  # BUILD THE SPACES FOR sed. # FIRST case DOES MULTIPLES OF 10; SECOND case DOES SINGLE SPACES: s="          "  # TEN SPACES case "$indent" in -?) ;;  # LESS THAN 10; SKIP IT -1?) pad="$s" ;; -2?) pad="$s$s" ;; -3?) pad="$s$s$s" ;; -4?) pad="$s$s$s$s" ;; -5?) pad="$s$s$s$s$s" ;; -6?) pad="$s$s$s$s$s$s" ;; -7?) pad="$s$s$s$s$s$s$s" ;; -8?) pad="$s$s$s$s$s$s$s$s" ;; -9?) pad="$s$s$s$s$s$s$s$s$s" ;; *)  echo "`basename $0`: Help! \$indent is '$indent'!?!" 1>&2; exit 1 ;; esac  case "$indent" in -0|-?0) ;;  # SKIP IT; IT'S A MULTIPLE OF 10 -1|-?1) pad="$pad " ;; -2|-?2) pad="$pad  " ;; -3|-?3) pad="$pad   " ;; -4|-?4) pad="$pad    " ;; -5|-?5) pad="$pad     " ;; -6|-?6) pad="$pad      " ;; -7|-?7) pad="$pad       " ;; -8|-?8) pad="$pad        " ;; -9|-?9) pad="$pad         " ;; *)  echo "`basename $0`: Help! \$indent is '$indent'!?!" 1>&2; exit 1 ;; esac  # MIGHT ADD expand FIRST TO TAKE CARE OF TABS: sed "s/^/$pad/" $*

First, the script sets the indentation amount, like -12 or -5 , in the indent variable. Next, it builds a shell variable, pad , with just enough spaces to indent the text. One case checks the first digit of $indent to find out how many ten-space chunks of spaces to put in pad . The next case finishes the job with a few more spaces. A sed ( 34.24 ) command adds the spaces to the start of each line. If your lines have TABs in them, change the last line to use expand or pr -e -t ( 41.4 ) and pipe the result to sed :

expand $* | sed "s/^/$pad/"