Category Archives: Basics
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.
man command, short for manual, provides help for the commands, utilities or function in Linux and Unix systems. Learn about usage , related packages, sections and other interesting facts about man pages.
Learn about the Solaris 10 & 11 certification , price, number of questoons , duration and direct links to official site for exam 1z0-876, 1z0-821 and more.
Here is the list of top 10 Linux distributions to free download latest version of linux operating system with links to linux documentation and home pages.
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.
Here is the top 10 must have books for system administartors who are starting working in Unix and Linux adminstration or current system administartors who want to improve skills and go deeper to learn and manage Unix and Linux systems.
Published several years ago these O’Reilly books are still useful & relevant for the current and new system administratiors. Although these books may not cover latest version of operating systems yet these explains very well the underlaying technical details and process which have not changed over the years.
Learn to use awk for text and data extraction, data processing, validation, generate reports for analysis, automation with with the help of examples of if else , compare & arrays plus regular expressions & built in operational variables, meaning, examples &command syntax.
CoPy In Out
Usage: cpio [OPTION…] [destination-directory]
GNU `cpio’ copies files to and from archives
# 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:
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
-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
–force-local Archive file is local, even if its name contains
-f, –nonmatching Only copy files that do not match any of the given patterns
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
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, –swap–bytes Swap the bytes of each halfword in the files
-S, –swap-halfwords Swap the halfwords of each word (4 bytes) in the
–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
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
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
-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
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
-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]>.