How do i make the history command to run from the script
I also want to redirect the output of the history command to a file

history >> /tmp/history.txt

when executed in a script is not working. when i checked out the net it said that history command will not work in the script

is there any mechanism by which i can get the history command to execute in a script?

Is there a particular reason why you don't use directly the history file /home/someuser/.bash_history ?

It will be available from any script for any user.

[root@cluster74 AmiNas]# history | wc -l
620
[root@cluster74 AmiNas]# cat /root/.bash_history | wc -l
559

This is the output i got from both. There is some difference between them... why is this?

After some searching in the bash man page (short explanation, have a look at the man page for options and env your can set to modify this behaviour)....
1- When you start a shell, the history is initialised from the history file
2- While you run the shell, the history is stored in a readline buffer specific to this shell (this is why you can have different histories in different buffers)
3- When the shell exits, the new commands in the history buffer are appended to the history file

Knowing this, I don't see how you can manipulate or even store the current shell history from a script. The only solution I can think of is to force the current shell to dump new commands to the history file before you run your script that will manipulate the history file but this requires some action in the current shell before launching the script. See options to history command in the bash man page for this.

Good luck.

i could get the output of the history command by running the script file in this manner
"./test.sh"

instead of "sh test.sh"

have you tried the 'script' command?
maybe it's what you need?