expand,
unexpand —
expand tabs to spaces, and vice versa
expand |
[ -t
tablist
]
[file ... ] |
expand processes the named files or the
standard input, writing the standard output with tabs changed into blanks.
Backspace characters are preserved into the output and decrement the column
count for tab calculations.
expand is
useful for pre-processing character files (before sorting, looking at specific
columns, etc.) that contain tabs.
unexpand puts tabs back into the data from
the standard input or the named files and writes the result on the standard
output.
The options are as follows:
-
-
-a- By default, only leading blanks and tabs are reconverted to maximal
strings of tabs. If the
-a option is
given, tabs are inserted whenever they would compress the resultant file
by replacing two or more characters.
-
-
-t
tablist- If the argument to
-t,
tablist, consists of a single numerical
argument, tabs are set tablist spaces
apart instead of the default 8. If multiple
-t options are given, then the tabs are
set at those specific columns.
Otherwise the argument to -t may consist
of a list of two or more positive decimal integers, separated by commas or
single blank characters, in ascending order: in the event of having to
process a ⟨tab⟩ at a position beyond the last of those
specified in a multiple -t list, the
⟨tab⟩ is replaced by a single ⟨space⟩
character.
This implementation of expand
additionally allows tablist to be
specified without using the -t flag, by
prefixing tablist with a dash (-).
The
expand and
unexpand utilities exit 0 on
success, and >0 if an error occurs.
fold(1)
The
expand and
unexpand utilities are compliant with the
IEEE Std 1003.1-2008
(“POSIX.1”) specification, except that this
implementation does not support a
-t flag
for
unexpand.
The ability to specify tabstops without the
-t flag is not specified by
IEEE Std 1003.1-2008
(“POSIX.1”), though it states it “may be present
in some implementations”.
The
expand utility first appeared in
1BSD.
![[OpenBSD]](/openbsd.gif){kind=small}