How To Execute Command During Booting

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Webune provides Linux Dedicated servers!!!

Today we are going to show you a little cool administration trick.

lets say for example you want to execute a shell command when your server starts to boot.

lets say for the purpose of this tutorial, we want to create a file called mylog.txt when the computer boots up.

#########:: step one is to login as root or login as superuser ::** #######

normally, if you are logged into your shell and if you send this command it will create a file called mylog.txt in the /root/ directory

SHELL COMMAND:

if you send this command it will create a file called mylog.txt and it will append with the following message:

LAST BOOT:
DATE: 02/27/10
TIME:18:14:57

ok, lets say i want to log the last time the server booted and write the time and date when this happen.

Some Linux distributions include a startup script that runs after the other SysV startup scripts. This script is generally called /etc/rc.d/rc.local, /etc/rc.d/boot.ocal or something similar. - NOTE that i am using a CentOS server, so if you have a RedHat or Fedora, it should be the file called /etc/rc.d/rc.local

WARNING: as humans we always make mistakes, so to cover ourselves, lets make a backup copy of the original /etc/rc.d/rc.local file with this command;

SHELL COMMAND:

since i am using CentOS, CentOS comes with nano as a text editor. you can use your favorite editor like VI if you want to.. so send this command to edit the /etc/rc.d/rc.local file:

SHELL COMMAND:

you might see something like this:


so add our command at the last line after touch /var/lock/subsys/local, so we add this:

date '+LAST BOOT:%nDATE: %m/%d/%y%nTIME:%H:%M:%S' > /root/test.txt

save the changes, now reboot your server

after the server has rebooted, view the contents of /root/test.txt with the cat command:



COOL!! now you should see the date has changed to when the server was last booted