— expand tabs to spaces, and vice
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.
puts tabs back into the data from the
standard input or the named files and writes the result on the standard
The options are as follows:
- 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.
- 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⟩
This implementation of expand additionally
allows tablist to be specified without
using the -t flag, by prefixing
tablist with a dash (-).
utilities exit 0 on success,
and >0 if an error occurs.
utilities are compliant with the
IEEE Std 1003.1-2008
specification, except that this
implementation does not support a -t
The ability to specify tabstops without the -t
is not specified by IEEE Std 1003.1-2008
, though it states it “may be present
in some implementations”.
utility first appeared in