UNIX for Dummies Questions & Answers

fold -w 20 filename

       -l N, --line-length=N

              specify the desired line-wrap length for the `l' command

OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0.8 (lenny) 
GNU sed version 4.1.5

#!/usr/bin/env bash

# @(#) s1	Demonstrate "list" command in sed.

# Utility functions: print-as-echo, print-line-with-visual-space, debug.
# export PATH="/usr/local/bin:/usr/bin:/bin"
pe() { for _i;do printf "%s" "$_i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
db() { ( printf " db, ";for _i;do printf "%s" "$_i";done;printf "\n" ) >&2 ; }
db() { : ; }
C=$HOME/bin/context && [ -f $C ] && $C

FILE=${1-data1}

pl " Input data file $FILE:"
cat $FILE

pl " Results:"
sed -n -l 20 'l' $FILE

exit 0

% ./s1

Environment: LC_ALL = C, LANG = C
(Versions displayed with local utility "version")
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution        : Debian GNU/Linux 5.0.8 (lenny) 
GNU bash 3.2.39

-----
 Input data file data1:
abcdefghij
12345678901234567890123456789012345678901234567890123456789012345678901234567890
abcdefghijklmnopqrst

-----
 Results:
abcdefghij$
1234567890123456789\
0123456789012345678\
9012345678901234567\
8901234567890123456\
7890$
abcdefghijklmnopqrs\;t
$