[glugot] One Day One GNU/Linux Command (FILE)

Bharathi Subramanian sbharathi at MidasComm.Com
Mon Apr 18 15:28:18 IST 2005

Mr Ramanraj K (ILUGC-Member & Lawyer) has developed "CALPP: Computer
Aided Legal Procedures and Proceedings".  It aids in defining  legal
procedures and executing those procedures as proceedings.  
URL: http://gborg.postgresql.org/project/calpp/projdisplay.php

One Day One Command :-

file -- Try to determine the FILE type.

Summary : 

File tests each argument in an attempt to classify it. There are 3
sets of tests, performed in this order: File System Test, Magic 
Number Test, and Language Test.

The File System test is based on examining the return from a stat(2)  
system call.  The program checks to see if the file is empty, or if
it's some sort of special file (block, char, pipe, ...).

The Magic Number test is used to check for files with data in
particular fixed formats. For example, a binary executable files will
have magic number in some fixed position to indicate the OS, that file
is executable. Few standard data files also following the magic number

The Language Test will happen, if a file does not match any of the
entries in the magic file. File will be checked for the ASCII, UTF8
ISO-8859-x, ... Char set. Once file has determined the character set
used in a text-type file, it will attempt to determine in what (prg)
language the file is written.

Unidentified file will classified as ``data''.


$ file myfile -- Print the file type.

$ file -b myfile -- Don't the filename in the output.

$ file -f list -- Take the input filenames (one per line) from the 
                  file 'list'.

$ file -k myfile -- Print all matches. 

$ file -z myfile.tgz -- Try to look into compressed file.

$ file -i myfile -- Print the output in MIME format.

$ file -m mymagic myfile -- Use custom magic file.

# file -s /dev/hda? -- Take blk/char special files as an argument.

Read: man file

Bye :)
Bharathi S
ODOC -- http://www.livejournal.com/community/ilugc/

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