Assign Output of Shell Command To Variable

Check Exit Status

Get the output of a command

Understand the difference between standard output and standard error

Some commands are not well-written, however, and may write information to the wrong place. You must keep an eye out for such commands, and work around them when necessary.

For example:

vers=$(python --version)
Python 2.7.13
echo "{$vers}"
{}

Even though we specifically asked for the version number, python wrote it to stderr. Thus, it appeared on the terminal, and was not captured in the vers variable. You'd need to use 2>&1 here.