chmod Quick Referance with Examples

What is chmod ?

chmod ( Change Mode ) is a command line utility in Unix , Linux and other Unix like systems to change the read, write, execute permissions of a file for owner , group and others.

How to use chmod?

Chmod command is used in two ways :
1. Using octal value & position : Sets the permission for owner, group and others with octal values , 4 for read , 2 for write , 1 for execute and any sum of these number to get cumulative permissions. Continue reading “chmod Quick Referance with Examples”

Linux Download : Top 10 Free Linux Distributions for Desktop and Servers

All the Linux distributions are either derivative of GNU/Linux ( OS made up of Linux Kernel developed by Linus Torvalds and GNU software repository) or derived from other Linux derivatives.

Desktop distributions comes with Graphical user interface enabled by default &   aimed at individual users and most of the administration work can be done using GUI. Good for new users and running Linux-based graphical applications.

Server Distribution are for more advanced users who are familiar with Linux command line as Graphical Interface is not enabled by default in most of the server distributions. Server distributions comes with web servers like apache  and networking packages like DNS and useful for running backend services , work as web server or DNS Server.

Continue reading “Linux Download : Top 10 Free Linux Distributions for Desktop and Servers”

cpio ( GNU )

CoPy In Out

Usage: cpio [OPTION…] [destination-directory]
GNU `cpio’ copies files to and from archives

Examples:
# Copy files named in name-list to the archive
cpio -o < name-list [> archive]
# Extract files from the archive
cpio -i [< archive]
# Copy files named in name-list to destination-directory
cpio -p destination-directory < name-list

Main operation mode:

-i, –extract
Extract files from an archive (run in copy-in
mode) -o, –create Create the archive (run in copy-out mode) -p, –pass-through Run in copy-pass mode

-t, –list Print a table of contents of the input

Operation modifiers valid in any mode:

–block-size=BLOCK-SIZE  Set the I/O block size to BLOCK-SIZE * 512
bytes
-B  Set the I/O block size to 5120 bytes
-c  Identical to “-H newc”, use the new (SVR4)
portable format.If you wish the old portable
(ASCII) archive format, use “-H odc” instead.
-C, –io-size=NUMBER  Set the I/O block size to the given NUMBER of
bytes
–force-local  Archive file is local, even if its name contains
colons
-f, –nonmatching Only copy files that do not match any of the given patterns
-F, –file=[[USER@]HOST:]FILE-NAME
Use this FILE-NAME instead of standard input or output. Optional USER and HOST specify the user and host names in case of a remote archive
-H, –format=FORMAT  Use given archive FORMAT
-M, –message=STRING  Print STRING when the end of a volume of the
backup media is reached
-n, –numeric-uid-gid In the verbose table of contents listing, show
numeric UID and GID
–quiet  Do not print the number of blocks copied
–rsh-command=COMMAND  Use remote COMMAND instead of rsh
-v, –verbose  Verbosely list the files processed
-V, –dot  Print a “.” for each file processed
-W, –warning=FLAG  Control warning display. Currently FLAG is one of
‘none’, ‘truncate’, ‘all’. Multiple options
accumulate.

Operation modifiers valid only in copy-in mode:

-b, –swap  Swap both halfwords of words and bytes of
halfwords in the data. Equivalent to -sS
-r, –rename  Interactively rename files
-s, –swapbytes Swap the bytes of each halfword in the files
-S, –swap-halfwords  Swap the halfwords of each word (4 bytes) in the
files
–to-stdout  Extract files to standard output

-E, –pattern-file=FILE  Read additional patterns specifying filenames to
extract or list from FILE
–only-verify-crc  When reading a CRC format archive, only verify the
checksum of each file in the archive, don’t
actually extract the files

Operation modifiers valid only in copy-out mode:

-A, –append  Append to an existing archive.
-O [[USER@]HOST:]FILE-NAME Archive filename to use instead of standard  output. Optional USER and HOST specify the user and host names in case of a remote archive

Operation modifiers valid only in copy-pass mode:

-l, –link  Link files instead of copying them, when
possible

Operation modifiers valid in copy-in and copy-out modes:

–absolute-filenames  Do not strip file system prefix components from
the file names
–no-absolute-filenames  Create all files relative to the current
directory

Operation modifiers valid in copy-out and copy-pass modes:

-0, –null  A list of filenames is terminated by a null
character instead of a newline
-a, –reset-access-time  Reset the access times of files after reading
them
-I [[USER@]HOST:]FILE-NAME  Archive filename to use instead of standard input. Optional USER and HOST specify the user and host
names in case of a remote archive
-L, –dereference  Dereference symbolic links (copy the files
that they point to instead of copying the links).
-R, –owner=[USER][:.][GROUP]  Set the ownership of all files created to the specified USER and/or GROUP

Operation modifiers valid in copy-in and copy-pass modes:

-d, –make-directories  Create leading directories where needed
-m, –preserve-modification-time
Retain previous file modification times when creating files
–no-preserve-owner  Do not change the ownership of the files
–sparse  Write files with large blocks of zeros as sparse
files
-u, –unconditional  Replace all files unconditionally

-?, –help  give this help list
–usage  give a short usage message
–version  print program version

Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options.

Report bugs to <[email protected]>.