The eval command allows you to run the contents of variables as commands and can be very useful -- especially in scripts.

In a previous column, I showed how to do substring expansion with shell variables in the form of $ {var:start:length}, but it's also useful to know the length of a variable's value. This can be done ...

Jack Wallen shows you how to pass environment variables to Docker containers for a more efficient development process.

I'm storing sensitive info like the auth token in environment variables. The problem is, the python script can only see them when I run the script manually from the shell (so I know that the code ...

Adding a Global Path in CentOS Linux. The "path" environment variable in Linux specifies the directories the terminal looks in when you type the path to a command. For example, when you type ...

Another special variable that you might have encountered is the status variable, $?. In a script, this contains the return value of the most recently executed (external) command. This is where you ...