NAME

file − determine file type

SYNOPSIS

file [−h] [−m mfile] [−f ffile] arg ...
file [−h] [−m mfile] −f ffile
file −c [−m mfile]

DESCRIPTION

file performs a series of tests on each file supplied by arg and, optionally, on each file supplied in ffile in an attempt to classify it.  If arg appears to be a text file, file examines the first 512 bytes and tries to guess its programming language.  If arg is an executable a.out, file prints the version stamp, provided it is greater than 0.  If arg is a symbolic link, by default the link is followed and file tests the file that the symbolic link references. 

−c Check the magic file for format errors.  For reasons of efficiency, this validation is normally not carried out. 

−f ffile ffile contains the names of the files to be examined. 

−h Do not follow symbolic links. 

−m mfile
Use mfile as an alternate magic file, instead of /etc/magic. 

file uses /etc/magic to identify files that have a magic number.  A magic number is a numeric or string constant that indicates the file type.  Commentary at the beginning of /etc/magic explains its format. 

FILES

/etc/magic

INTERNATIONAL FUNCTIONS

file can classify files containing characters from supplementary code sets.  file reads each argument and can distinguish data files, program text files, shell scripts and executable files as follows:

SEE ALSO

filehdr(4). 

DIAGNOSTICS

If the −h option is specified and arg is a symbolic link, file prints the error message:

symbolic link to arg

  —  Essential Utilities