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Thursday, November 26, 2015

Basic File Extensions

File Extension
Refers to text file
Refers to Graphics interchange format image
Refers to Joint Photographic Experts Group image
Refers to MPEG-2 Layer 3 audio
Regers to compressed file
Regers to Unix ‘tape arhive’file
Refers to compressed archive file

Visiting Directories with cd
·  You can change to other directory from the current working directory by using the cd command.  For exaple if you want src to be your current directory, then type the following

$ cd /usr/src

·     If you donot give the directory name as an argument, the cd command navigates you to the home directory.
You can use pwd command to find out the current directory. Syntax for finding the current directory is : $ pwd
V.  filename Completion
·           Modern shells jprovides you ne of the most useful features of the Linux command line that is automatic file name completion. You do not have to type to type the complete file names at the Linux command line.  Type only the beginnging f a file name in the command line and press the Tab key and the shell sbompletes the rest.
·                    There may be several files that start with the same letters but have different endings.  When you have typed the first letters of a file name and press the Tab key, the shell completes as much as it can and beeps.  When you press the Tab key againn, the shell shows you all the alternatives.

i.        Wildcard patterns
·               Give commands multiple files by specifying patterns
·              You can use the * symbol to match any part of a filename.  For example:
$ ls *.txt
Accounts.txt letter.txt report.txt
ii.          Copying Files with cp
·           You can copy files by using the syntax:
Cp [options] source-file destination-file
·            You can copy multiple files into a directory by using the syntax:
Cp files directory
·                 Common options used with cp  comand are:
  • -f: overwites the destination files
  • -i: prompts you befor overwriting files
  • -a: archive, copy the contents of directories recursively
i.             Examples of Cp command
·                       Copy /etc/smb.conf to the current directory
           $ cp /etc/smb.conf
·                       Create an identical copy of a directory called work, and call it work –backup:
$ Cp –a work work-backup

·        Copy all the GIF and JPEG images in the current directory into images:
$ Cp *.gif*. jpeg images/

ii.              Moving Files with mv
·                          You can rename files or directories, or move them to different directories by using the mv command
·                    Options used with mv command:
  • -f: overwrites the destination file, even if target aleady exists
  • -i: asks user interactively before overwiting files

·        For example, to rename poetry.txt to poems.txt, the command is:

$ mv poetry. Txt poems.txt

·        To move the content of the current directory at some other laocation, the command is :
$ mv * -/old-stuff/

Basic File Managemant (Part-2)

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