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

$ sh test.sh I love "Linux Journal" you gave me 3 variables and the first is I unprotected parameters: I was given 4 parameters or, more succinctly: I was given 4 parameters but when we put $* in ...

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 ...

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 ...

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