Shell Configuration File: `~/.bashrc`¶

What’s Volatile?¶

Settings from the commandline aren’t usually persistent
Tuning the PATH environment variable is in effect only for the current shell/process and for all of its descendants
Nobody outside that shell’s process tree can see the modification (environment variables are inherited after all)

After a reboot, they are definitely gone

$ PATH=/home/jfasch/bin:$PATH
$ export PATH

Same with shell aliases
```
$ alias d='ls -al'
```

Solution: ~/.bashrc

Write everything that needs to persist (and is re-initialized at every login) in ~/.bashrc
Read be every shell that starts up

“Sourcing” a file

If you do not want to quit your running shell, you can always re-read the file into the current shell, by “sourcing” it
```
$ . ~/.bashrc
```
or, equivalently,
```
$ source ~/.bashrc
```