9.3 unexpand: Convert spaces to tabs

unexpand writes the contents of each given file, or standard input if none are given or for a file of `-', to standard output, with strings of two or more space or tab characters converted to as many tabs as possible followed by as many spaces as are needed. Synopsis:

unexpand [option]... [file]...

By default, unexpand converts only initial spaces and tabs (those that precede all non space or tab characters) on each line. It preserves backspace characters in the output; they decrement the column count for tab calculations. By default, tabs are set at every 8th column.

The program accepts the following options. Also see 2. Common options.

`-t tab1[,tab2]...'

`--tabs=tab1[,tab2]...'

If only one tab stop is given, set the tabs tab1 spaces apart instead of the default 8. Otherwise, set the tabs at columns tab1, tab2, ... (numbered from 0), and leave spaces and tabs beyond the tabstops given unchanged. Tabstops can be separated by blanks as well as by commas. This option implies the `-a' option.

On older systems, unexpand supports an obsolete option `-tab1[,tab2]...', where tabstops must be separated by commas. (Unlike `-t', this obsolete option does not imply `-a'.) POSIX 1003.1-2001 (see section 2.5 Standards conformance) does not allow this; use `--first-only -t tab1[,tab2]...' instead.

`-a'

`--all'

Convert all strings of two or more spaces or tabs, not just initial ones, to tabs.