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
expand [option]… [file]…
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.
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.
As a GNU extension the last tab specified can be prefixed with a ‘/’ to indicate a tab size to use for remaining positions. For example, --tabs=2,4,/8 will set tab stops at position 2 and 4, and every multiple of 8 after that.
Also the last tab specified can be prefixed with a ‘+’ to indicate a tab size to use for remaining positions, offset from the final explicitly specified tab stop. For example, to ignore the 1 character gutter present in diff output, one can specify a 1 character offset using --tabs=1,+8, which will set tab stops at positions 1,9,17,…
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.