Published January 29, 2011 by

Unix Miscellaneous commands

  1. ls
  2. pwd
  3. ln
  4. head
  5. tail
  6. cal
  7. ps
  8. kill
  9. who
  10. whoami
  11. uptime
  12. ut
ls : This command displays files and directories in columnar format.


Example:


$ ls


$ ls -S                

Aarrange the files based on the size(S is upper letter)


$ ls -l                

long listing the files


$ ls -a                

Displays hidden files


$ ls -i 

Displays inodes for each file


$ ls -R            

Displays all directories along with subdirectories in current working directory.


creating a hidden file:


$ cat >.employee.txt            


Wild card characters using with ls command.


 Represents single character
*   Represents gruop of characters
[  ]   Represents searching pattern


Examples:


$ ls ?                Displays files with one letter


$ ls x*               Displays files which are starting with 'x'


$ ls ???           Displays files with 3 letters


$ ls *.out          Displays all the files with extension 'out'


$ ls [a-z]           Displays single character files which are from a to z


$ ls [a-z]*          Displays files starting with a to z


$ rm ?               Removes the files with single character


$ rm *.c             Removes the files with extension 'c'


$ cp ? chennai       Single digit files will be copied into directory 'chennai'


pwd : This command shows current working directory in unix


$ pwd



head :  Used to display First lines of the file


Syntax:


$ head -n  filename


Example:


$ head  paypal.txt


     This command dispalys default 10 lines of the file paypal.txt


$ head -n15  paypal.txt


    This command displays 15 lines of the file paypal.txt


$ head -n3  paypal.txt


    This command displays 3 lines of the file paypal.txt


tail : Used to display last lines of the file.


Ex:


$ tail paypal.txt


      This command displays default last 9 lines.


$ tail -n5 paypal.txt


      This command displays last 4 lines of the file.


$ tail -n15 paypal.txt


       This command displays last 14 lines of the file.


cal command: Used for display the calender.


Syntax:


$ cal


$ cal  [Month No] [Year]


Ex:


$ cal 2011                Displays 2011 calender


$ cal  2   2011          Displays Feb month in 2011 year


ln :


1.This will create link between 2 files.(2nd file should new one)


2. If one file modified another one affected.


Ex:


$ln paypal.txt    funpal.txt


ps : Knowing backgroud process running /stopped


$ ps pid     


kill : Used for terminating the process


Ex:


$ kill  pid


who : Used for to display who are working in the system


Ex:

$ who

whoami: Display my user name/accout


Ex:


$ whoami


uptime: This command used for display load in the server.


$ uptime


ut: displays current unix time

advance_date : Used to time forward the unix server.

$ advance_date

reset_time.py : Used to reset time and date in unix server.

$ reset_time.py



    email this