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9.2 expand: Convert tabs to spaces

expand writes the contents of each given file, or standard input if none are given or for a file of ‘-’, to standard output, with tab characters converted to the appropriate number of spaces. Synopsis:

expand [option]… [file]…

By default, expand converts all tabs to spaces. It preserves backspace characters in the output; they decrement the column count for tab calculations. The default action is equivalent to -t 8 (set tabs every 8 columns).

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

-t tab1[,tab2]…

If only one tab stop is given, set the tabs tab1 spaces apart (default is 8). Otherwise, set the tabs at columns tab1, tab2, … (numbered from 0), and replace any tabs beyond the last tab stop given with single spaces. Tab stops can be separated by blanks as well as by commas.

For compatibility, GNU expand also accepts the obsolete option syntax, -t1[,t2]…. New scripts should use -t t1[,t2]… instead.


Only convert initial tabs (those that precede all non-space or non-tab characters) on each line to spaces.

An exit status of zero indicates success, and a nonzero value indicates failure.