35.8 Centering Lines in a File

Here's an awk script, written by Greg Ubben, that centers lines across an 80-character line. If your system understands #! ( 44.4 , 45.3 ) , this script will be passed directly to awk without a shell. Otherwise, put this into a Bourne shell script ( 44.14 ) :

#!/usr/bin/awk -f
{
    printf "%" int(40+length($0)/2) "s\n", $0
}

For each input line, the script builds a printf command with a width specification (like % width s ) that's just wide enough to center the line.

In vi , you can use a filter-through ( 30.22 ) command to center lines while you're editing. Or just use center from the command line. For example:

% 

center afile > afile.centered


% 

sort party_list | center | lp