Shell Programming and Scripting

I need help with a script. Here's what I want to do.

I have a file "upsrk.txt" which can be either under "/home/upsrk" OR "/home/oracle"

On some systems file "upsrk.txt" may not exist, in that case I want to just exit out of the script.

If the file is there, I want to check if I have the permissions to write to this file (on some systems it may be owned by root)

If I have the permissions to this file, then I want to look for "upsrk@gmail.com" and then comment the line which contains it.

Thanks in Advance for your Help.

Won't write the whole script for you.
Re the comment out, you can use:

Code:

sed  's/\(.*upsrk@gmail.com.*\)/#\1/' filename

To check if file exist you can use if [ -f "${FILENAME}" ] .

More generally, the test command (aka opening square bracket [ command) has a number of operators for checking file permissions. test -w file checks if you have write access, test -d file checks if it's a directory, etc.

Thank Ynir and era

I am new to the script, would greatly appreciate if you can tell how to put all of this together in a script.

Thanks Again for your help