bash refer parameters from the current command

2014-09-15 1 min read Bash

In bash you can use

to refer to any parameter from the current command, example:

mv ak amit.!#:1.txt
ls amit.ak.txt

Debuggging bash cron scripts.

2014-09-01 1 min read Bash Learning

I have to several times debug scripts that I get complain about working when logging in normally but they do not work when run in cron mode. So, quite a lot of times, redirecting the stderr of the script is all that is required to see what is happening, but sometimes that just does not help if the script is calling another script which is mis-behaving and under lot of other conditions. So, how to at-least take a look at why these are failing, login with ssh.

bash debug – log all executed commands

2014-02-03 1 min read Bash

Whenever I am writing a script in perl or bash, I always wish that there
was some way to have all the commands logged or output to screen. I know
there is “set -x” option to have debugging enabled, but sometimes that
seems to be too much information and I dont really need all that. So, here
is something I found recently for bash to log all the executed commands.

bash – using the vi mode more effectively.

2013-11-22 1 min read Bash

Vi blogging bundle (Photo credit: pedro mg)

You can first set the bash mode to vi. This will enable some vim like features to bash. So, add this to .bashrc :

set -o vi

Once, you have done that then its time to get more out of the vi mode. First, check some things and set some interesting stuff.

bashrc with lots of functions and useful alias

2013-10-30 1 min read Bash

Here is a link of a useful 10K lines bashrc

http://pastebin.com/LEkXXuST

You may not want to put the whole thing, but get an idea and use what you think can be helpful to you or at-least get an idea. This was not posted by me, so if you are re-using code as is, check the permissions to copy.

poor mans watch, watch for solaris

2013-01-01 1 min read Bash Solaris

Here is a simple script that you can use as watch in Solaris as well.

watch()
{
    #Poor man's watch
    while (true)
    do
        clear
        $*
        sleep 2;
    done
}

Disable a few cores when you want to save power.

2012-12-28 2 min read Bash Fedora Linux

If you have a lot of CPU power and working on battery. If you do not need that much of power and would like to rather save some battery power by disabling some cpus then you can use the below script. This script disables cpus from 4 to 7. You can change the number in the for loop. You would need the sudo to be setup or remove sudo and run the script as root. The script will show you the currently active cpu’s before and after disabling the CPU’s.

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