linux-commands.md

Run A Script On Boot

This is a simple way of having a script run on startup:

1. Create a file for your startup script and save your script in it.

   sudo vim /etc/init.d/<NAME_OF_SCRIPT>
   

   Here is an example script:

   #! /bin/sh
   # /etc/init.d/noip 
   
   ### BEGIN INIT INFO
   # Provides:          noip
   # Required-Start:    $remote_fs $syslog
   # Required-Stop:     $remote_fs $syslog
   # Default-Start:     2 3 4 5
   # Default-Stop:      0 1 6
   # Short-Description: Simple script to start a program at boot
   # Description:       A simple script from www.stuffaboutcode.com which will start / stop a program a boot / shutdown.
   ### END INIT INFO
   
   # If you want a command to always run, put it here
   
   # Carry out specific functions when asked to by the system
   case "$1" in
   start)
       echo "Starting noip"
       # run application you want to start
       /usr/local/bin/noip2
       ;;
   stop)
       echo "Stopping noip"
       # kill application you want to stop
       killall noip2
       ;;
   *)
       echo "Usage: /etc/init.d/noip {start|stop}"
       exit 1
       ;;
   esac
   
   exit 0
   

2. Make the script executable

   sudo chmod 755 /etc/init.d/<NAME_OF_SCRIPT>
   

   Test starting the script:

   sudo /etc/init.d/<NAME_OF_SCRIPT> start
   

   Test stopping the script:

   sudo /etc/init.d/<NAME_OF_SCRIPT> stop
   

3. Register the script to be run at start-up

   sudo update-rc.d <NAME_OF_SCRIPT> defaults
   

   If you ever want to remove the script from start-up, run the following command:

   sudo update-rc -f <NAME_OF_SCRIPT> remove
   

Run a script on login

This is a simple way of having a script run on startup:

1. Create a file for your login script and save your script in /etc/profile.d/

   sudo vim /etc/profile.d/<NAME_OF_SCRIPT>
   

   Here is an example script:

   #!/bin/sh
   sudo mount -t vboxsf -o rw,uid=1000,gid=1000 share ~/host
   

2. Make the script executable

   sudo chmod 755 /etc/profile.d/<NAME_OF_SCRIPT>
   

Check System Utilization

Check Top Processes

$ top

• Press shift+e to change KB to MB in memory section
• Press q to quit

Check Memory Utilization

$ free -m

Watch
Watch is used to run any designated command at regular intervals. The time interval between each report can be set using the -n flag followed by an integer that represents the desired number of seconds

$ watch -n 5 free -m