Linux Commands - Quontra Solutions

Information about Linux Commands - Quontra Solutions

Published on August 25, 2014

Author: quontra123

Source: authorstream.com

Content

Linux Commands: Linux Commands File Handling Call Us : 404-900-9988 Email: [email protected] Website: www.quontrasolutions.com Topics: Topics head tail link tar gzip and gunzip touch diff ‘head’ command: ‘head’ command Displays the first ten lines of a file, unless otherwise stated. Syntax : head [-number | -n number] filename Example: head -15 myfile.txt It displays the first 15 lines of ‘myfile.txt’ . -number Number of lines to display -n number Number of lines to display filename Desired filename ‘tail’ command: ‘tail’ command Displays the last ten lines of a file, unless otherwise stated. Syntax : tail [-n number] [-l] [-b] [-c] [-r] [-f] [file] -n number Number of lines to display -l Units of lines. -b Units of blocks. -c Units of bytes. -r Copies lines from the specified starting point in the file in reverse order. -f Displays the last 10 lines and then update the file as new lines are being added. filename Desired filename ‘link’ command: ‘link’ command Creates a link to the file or directory. Syntax : ln [-f] [-n] [-s] [-i] source destination -f Forced to create a link. -n Does not overwrite existing files. -s Creates a Symbolic link. source Desired filename destination Destination filename PowerPoint Presentation: Example: ln –s f1 home/myfiles/f2 Creates a symbolic link between file ‘f1’ to file ‘f3’ of ‘myfiles’ directory. Represented as ‘ ’ View the Link using : ls –l Remove the link using ‘ rm’ command. rm –r f1. ‘tar’ command: ‘tar’ command Used to group set of files in to ma single file. It is called Archive file. Syntax : tar [-c] [-t or -v] [-x] [-f] filename archivefilename It has ‘.tar’ extension. -c Creates an archive file. -t or -v Lists archive file content. -x Extract or de archive an archive file. filename File to be archived archivefilename New name for archive file. PowerPoint Presentation: Examples: Create an archive file tar –vcf dir1 myarc.tar It creates archive file ‘myarc.tar’ which has all files of directory ‘dir1’. 2. Dearchive an archive file tar –xvf myarc.tar All files in ‘dir1’ are no more grouped, they are separated. ‘gzip’ and ‘gunzip’: ‘gzip’ and ‘gunzip’ Used to compress and decompress the file respectively. Syntax : gzip [-f][-d] filename. gunzip [-f] compressedfilename. It is with ‘.gz’ extension . -f Compress forcibly. -d Decompress the compressed file. filename File to be compressed. PowerPoint Presentation: Examples: Compress the file. gzip –f f1. Compresses the file ‘f1’ and is represented as ‘f1.gz’. 2. Decompress the compressed file. gzip –d f1.gz or gunzip –f f1.gz File ‘f1.gz’ is decompressed to file ‘f1’. ‘touch’ command: ‘touch’ command Used to change the timestamp of a file. It is also used to create multiple files at one shot. Syntax: touch –t [-a][-m] [-r reference-file] filename a To change access time m To change modified time -r Refer the timestamp of another file filename Required filename PowerPoint Presentation: Use ‘ Stat ’ command to know the Timestamp. $ stat f1.c (sample output) Access: 2010-11-01 20:35:58.000000000 +0530 Modify: 2010-11-01 20:35:58.000000000 +0530 Change: 2010-11-01 20:35:58.000000000 +0530 Format for touch -t is : [YY]MMDDhhmm[.ss] PowerPoint Presentation: Examples : Create multiple files at once. $ touch file1.txt file2.txt file3.txt 2. Change the access time of a file. $ touch –t -a 08210820 file1.txt Access: 2010-06-15 13:30:00.000000000 +0530 Modify: 2010-08-21 08:20:00.000000000 +0530 Change: 2010-11-01 20:45:05.000000000 +0530 PowerPoint Presentation: Same way we can change the modified time of a file using ‘-m’ along with ‘-t’ 4. Refer the timestamp of another file than the current time. $touch -r file4 file5 file 5 uses the timestamp of file4. ‘diff’ command: ‘diff’ command It is used to find differences between two files. Syntax: diff [options] file1 file2 Options : a Treats all files as text and compare them line-by-line. y Use the side by side output format. w Ignore white space/blank space when comparing lines. i Ignores Case. PowerPoint Presentation: Let us have two files, file1.txt and file2.txt as follows: file1.txt file2.txt LINUX TEST goodmorning with great thoughts Lead india LINUX TEST GOODMORNING with   great   thoughts PowerPoint Presentation: Examples : 1. Compare the files side by side, ignoring white space. diff -by file1.txt file2.txt LINUX TEST LINUX TEST hscripts.com | HSCRIPTS.com with great thoughts with great thoughts Lead India < 2. Compare the files side by side, ignoring Case. diff -iy file1.txt file2.txt LINUX TEST LINUX TEST hscripts.com HSCRIPTS.com with great thoughts | with great thoughts Lead India < PowerPoint Presentation: Thankyou

Related presentations


Other presentations created by quontra123