The command to address this issue is “chmod”. There is more than one way to change permissions, but I prefer the OCTAL code method. This method can be memorized easily using the following table.

As with many things on the Linux command line, you have some choices on how you make your requests. The chmod command allows you to change permissions numerically or using character expressions.

I often profess that Linux can be used without the command line, but at some point, you might want to learn it anyway. When you do, consider these commands.

The chmod operation allows the file owner to run a shell script. Note that “777” is too permissive for most environments. Finally, when you run an Linux shell script in an Ubuntu terminal window, you ...

A restrictive chmod command provides for non-repudation (i.e., a user cannot claim that a file that he creates is not his).

This series of posts will help Linux/Unix newbies to feel comfortable on the command line.