How To Bash Script For Mass Changes

You can use some bash scripting to make for loops and have mass changes in a Linux Server. Follow the simple steps below.

Collect the data that is needed to be changed.

• Here we will use the “find” command to look for 777 directories under user “whomever.”
• find /home/whomever/public_html -type d -perm 777
• What this does is find in directory /home/whomever/public_html, any directories (-type d) that are 777 permissions (-perm 777).
• You can change this to work with whatever directories you want, permissions you want, etc.

Alright that’s neat, but kind of hard to read if you have a lot of 777 permissions in this directory. Let make them all go into a file.

• Start with the same command, but we’ll add something to make it go into a file we create.
• find /home/whomever/public_html -type d -perm 777 > badpermlist
• What this does is take our query and creates a file called “badpermlist” where all the data will be put.

Now that we have our data, we can start with some basic scripting.

Verify your data

• for each in `cat badpermlist` press -enter-
• do press -enter-
• ll -d $each press -enter-
• done | more press -enter
• This will show your data that is in the file.
• IMPORTANT: the ` ` marks are the ones that are under the ~ key, NOT the apostrophe key

Change the data

• for each in `cat badpermlist` press -enter-
• do press -enter-
• chmod 755 $each press -enter-
• done press -enter-
• Congrats, you just changed all those pesky 777 permissions to 755 like they should be.

Verify that the change took place because it is never a bad idea to check your work.

• for each in `cat badpermlist` press -enter-
• do press -enter-
• ll -d $each press -enter-
• done | more press -enter-
• Now all the data that showed up as 777 should now show as 755.

Now as you can tell, there is a lot of potential to a very simple script like this. I hope this helps breakdown some basic concepts for you and helps you on your scripting way!

Note

• Play with changing the items specified in a “for loop,” just remember what you changed so you can change it back!
• Watch that you use the ` ` (backwards apostrophes) symbols under the ~ (til-day). If you use ‘ ‘ (apostrophes) it will NOT work!