Chapter 21
What's In Your Environment (env, echo, Env:)
21.1 Do This
TERM_PROGRAM=Apple_Terminal
TERM=xterm
SHELL=/bin/bash
OLDPWD=/Users/zed/temp
USER=zed
COMMAND_MODE=unix2003
PATH=/opt/local/bin:/opt/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/usr/X11/bin
PWD=/Users/zed/
LANG=en_US.UTF-8
PS1=$
SHLVL=1
HOME=/Users/zed
LOGNAME=zed
_=/usr/bin/env
$ env | grep zed
OLDPWD=/Users/zed//temp
USER=zed
PWD=/Users/zed/
HOME=/Users/zed
LOGNAME=zed
$ echo $USER
zed
$ echo $PWD
/Users/zed/
$ export TESTING="1 2 3"
$ echo $TESTING
1 2 3
$ env | grep TESTING
TESTING=1 2 3
$
21.2 You Learned This
Your shell has these "hidden variables" that can change how other programs work. In this exercise I first print out my environment, just dumping it to the screen. Then I do it again but pipe it through grep to find only the variables with my username in them. Finally, I set an environment variable TESTING to "1 2 3".
You may not run into this too often, but sometimes to get something configured you have to change these. A good example is the PATH variable, which determines the search order for other commands. Changing your PATH is going to be one of your exercises.
21.3 Do More
- I want you to go online and research how you change your PATH for your computer. Try to do it entirely from the CLI.
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