EXPAND(1) BSD Reference Manual EXPAND(1)
expand, unexpand - expand tabs to spaces, and vice versa
expand [-tabstop] [-tab1,tab2,...,tabn] file ...
unexpand [-a] file ...
Expand processes the named files or the standard input writing the stan-
dard output with tabs changed into blanks. Backspace characters are pre-
served into the output and decrement the column count for tab calcula-
tions. Expand is useful for pre-processing character files (before sort-
ing, looking at specific columns, etc.) that contain tabs.
If a single tabstop argument is given, then tabs are set tabstop spaces
apart instead of the default 8. If multiple tabstops are given then the
tabs are set at those specific columns.
Unexpand puts tabs back into the data from the standard input or the
named files and writes the result on the standard output.
Option (with unexpand only):
-a By default, only leading blanks and tabs are reconverted to maximal
strings of tabs. If the -a option is given, then tabs are inserted
whenever they would compress the resultant file by replacing two or
The expand command appeared in 3.0BSD.
4th Berkeley Distribution June 9, 1993 1