WHAT(1) | General Commands Manual | WHAT(1)

# NAME

`what` — show what versions of object modules were used to construct a file

# SYNOPSIS

`what` | [`-s`] file ...

# DESCRIPTION

`what` reads each file and searches for sequences of either the form ‘$’ immediately followed by the system name (sysname) as defined by uname(3), or the form “@(#)” as inserted by the source code control system (SCCS).

When ‘$’ followed by the system name is encountered, `what` prints the remainder of the string up to a ‘$’ or any non-printable character.

When “@(#)” is encountered `what` prints the remainder of the string, up to a NUL, newline, double quote, backslash, or ‘>’ character.

If the `-s` option is specified, only the first occurrence of an identification string in each file is printed.

# EXIT STATUS

The `what` utility exits with a return value of 0 if any identification strings were found, or with a return value of 1 otherwise.

# STANDARDS

The `what` utility is compliant with the X/Open System Interfaces option of the IEEE Std 1003.1-2008 (“POSIX.1”) specification.

Processing $sysname$ sequences is an OpenBSD extension.

# HISTORY

The `what` command first appeared in the SCCS package and was rewritten for 4.0BSD for licensing reasons.

March 31, 2022 | Debian