How to redirect output of script to a file(Need to save log in a file and file should be menioned in the script itself?

Expectation : @subject

Steps :

1. Create a bash script.
2. add line : exec > >(tee /var/log/my_logfile.txt)

That's it. All output of echo will be saved in this file.

Example :

[root@vm68 log]# cat /etc/init.d/crond |head -2
#! /bin/bash -x

[root@vm68 log]# cat /etc/init.d/crond |head -5
#! /bin/bash -x

exec > >(tee /var/log/my_cron_logfile.txt)

#
[root@vm68 log]#reboot

OP :

[root@vm68 log]# cat /var/log/my_cron_logfile.txt
Starting crond: [ OK ]

As per your need try to modify the script and echo. OP will go to this file.