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Full Discussion: Please explain setuid bit clearly!
Operating Systems Linux Please explain setuid bit clearly! Post 302601200 by vishal_vsh1 on Thursday 23rd of February 2012 05:36:36 AM
Old 02-23-2012
Every thing in Linux is considered as file.

you can run following command to know the type of the file.

Code:
$ file /sbin/iptables
/sbin/iptables: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.15, stripped
$file /bin/ping
/bin/ping: setuid ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.15, stripped

the above result says that they are binary files and all information about those binaries are given.

lets take example of a script.

Code:
$file update.sh
update.sh: Bourne-Again shell script text executable

this meand update.sh is a borne shell script.

lets take simple text file.
Code:
$file setup.conf
subversion.conf: ASCII text

some other format.

Code:
$file ldap.tar
ldap.tar: POSIX tar archive (GNU)

I think now you must have understood the file concept and how to know the file type.

Note- In Linux file extension does not matter and it may not give a exact picture of file type.
Last edited by vishal_vsh1; 02-23-2012 at 07:29 AM.. Reason: adding code format
This User Gave Thanks to vishal_vsh1 For This Post:
all4cfa
 

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LEARN ABOUT DEBIAN

cfourcc

cfourcc(1)							   User Commands							cfourcc(1)

NAME

       cfourcc - tool for changing FourCC in Microsoft RIFF AVI files

SYNOPSIS

	 cfourcc [-i] <file.avi>
	 cfourcc -u <CODE> <file.avi>

OPTIONS

       -h  Show summary of options.

       -d CODE
	   Sets FOURCC codec decription string.

       -f  Force changing FOURCC on unsupported file

       -i  Display FOURCC information (default).

       -u CODE
	   Set FOURCC codec.

	   None.

DESCRIPTION

       Program identifies the codec used in AVI files (*.avi) and allows the user to change the FourCC description code (like fourcc-changer in
       Windows). Useful for people working with Microsoft AVI file. A Linux clone of AviC fourcc changer tool.

EXAMPLES

       Note that you only need to change the -u codec field most of the time and not touch the -d description:

	   cfourcc -u DIVX -d DIVX file.avi

ENVIRONMENT

       None.

FILES

       None.

SEE ALSO

       ffmpeg(1) mplayer(1)

AUTHORS

       cfourcc was written by Mohammad Hafiz bin Ismail aka "mypapit" <info@mypapit.net>.

       This manual page was written by Jarno Elonen <elonen@debian.org>, for the Debian project (but may be used by others). Updated by Jari Aalto
       <jari.aalto@cante.net>. Released under license GNU GPL v2 or (at your option) any later version. For more information about license, visit
       <http://www.gnu.org/copyleft/gpl.html>.

cfourcc 							    2012-04-02								cfourcc(1)
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