expand [-t tablist][file ...]
The expand utility shall write files or the standard input to the standard output with <tab>s replaced with one or more <space>s needed to pad to the next tab stop. Any <backspace>s shall be copied to the output and cause the column position count for tab stop calculations to be decremented; the column position count shall not be decremented below zero.
The expand utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following option shall be supported:
If a list of tabstops is given, the application shall ensure that it consists of a list of two or more positive decimal integers, separated by <blank>s or commas, in ascending order. The tabs shall be set at those specific column positions. Each tab stop N shall be an integer value greater than zero, and the list is in strictly ascending order. This is taken to mean that, from the start of a line of output, tabbing to position N shall cause the next character output to be in the ( N+1)th column position on that line.
In the event of expand having to process a <tab> at a position beyond the last of those specified in a multiple tab-stop list, the <tab> shall be replaced by a single <space> in the output.
The following operand shall be supported:
See the INPUT FILES section.
Input files shall be text files.
The following environment variables shall affect the execution of expand:
Default.
The standard output shall be equivalent to the input files with <tab>s converted into the appropriate number of <space>s.
The standard error shall be used only for diagnostic messages.
None.
None.
The following exit values shall be returned:
The expand utility shall terminate with an error message and non-zero exit status upon encountering difficulties accessing one of the file operands.
The following sections are informative.
None.
None.
The expand utility is useful for preprocessing text files (before sorting, looking at specific columns, and so on) that contain <tab>s.
See the Base Definitions volume of IEEE Std 1003.1-2001, Section 3.103, Column Position.
The tablist option-argument consists of integers in ascending order. Utility Syntax Guideline 8 mandates that expand shall accept the integers (within the single argument) separated using either commas or <blank>s.
None.
tabs , unexpand