Basic linux commands


==>>>   Command


             






                
                - date                          : to see the date and time
                - date 112503451982 : month,date,hour,minut,year                        
                - cal                            : to see the calendar
                - cal 2010                   : to see the calendar of 2010
                - cal 5 2010                : display the calendar of May 2010                                        
                - clear                         : to clear the screen
                - ls                              : to see the list of dir and file                   
                - useradd vishal           : to create user with name 'vishal'
                - passwd vishal            : to set & also change password of user 'vishal'
                - passwd                     : to root only

                - passwd -d vishal                  : create user without password
                - usermod -l n-name o-name  : to rename user
                - usermod -g group user         : to add user in group
                - useradd -n vishal                  : create user without duplicate directory
                - userdel vishal                        : to delet user
                - userdel -r vishal                    : Delet user with their directory
                - rm -rf directory                    : forcefuly remove directory

                - groups vishal                         : to see membarship of user
                - vi /etc/passwd                       : see user directory
                - groupadd sels                        : create group
                - vi /etc/group                          : see group directory

                - groupmod -n n-name o-name  : rename group

                - su macho           : to login one user to other user (sudo passwd vishal)
                - system-config-   : to see graphycaly any configuration
                - ctrl+shift-t          : create a new Tab
                - ctrl+PgUp/Dn    : Switch to next/prev
                - /usr/share/doc    : to see file of any command
                 (cp,cd & ls -l    /usr/share/doc/HTML/index.html)
   
               

                - whatis cal           : to see help about any calendar
                - date --help         : to see detailed help about date
                - man ls                : to see manual page about ls
                - info history         : to information of history
                - which dir            : to find path of any directory & command




=> Tilde ( ~ )     (May refer to your home directory)
                           cat ~/.bash_profile
                           ls ~sam/public_html


 

=> system-config-date                  to set date & time graphicaly


=> history     (this command is used to see recently used command)


=> ping vishalvyas.com
=> ping -w4 vishalvyas.com
=> ping -c4 vishalvyas.com > test
=> ll >>test

=> renice 5 PID          reduce the priority

=> kill 3428                used to kill particular process with pid

=> top (CLI)              used to see process list, memory and cpu uses

=> gnome-system-monitor    ( GUI ) 

=> ctrl+c                     fully stop

=> ctrl+d                    stop terminal

=> ctrl+z                     send the program into background or temp. halt (ping,firefox)

=> jobs                       used to check the program running into back.

=> fg 1 or 2 or 3         used to bring halt program to rerun

=> at 0630                  to schedule these all jobs at 06:30

   > mkdir /root/Desktop/macho
   > useradd macho
   > ls -l
   > ctrl+d
Note : at command runs programme only ones at particular time

=> atq                         to see pending jobs

=> atrm 4                    to remove job-no. 4

=> crontab -e              this command is used to execute the job
            manytime as you want (chep-4)

=> who | wc -l > abc.txt    example of grouping multi command

=> date; who | wc -l >> abc.txt     grouping command

=> $?                used to check the last command status
            0     for     success
            1-255     for     error  

 => date 010101012010
           [MMDDhhmmYY]

                month  : MM
                date     :  DD
                hours   :  hh
                minute  : mm
                year     : YY
above example will set the date

 1st of JAn, at 01:01:01am. and the Year 2010

                - startx  : initialize an X session (if ur mode in text through this command u can get Graphical mode).


Thanks,
Vishal Vyas