1.7. Exercises

1. Where is the bash program located on your system?

$ which bash
/bin/bash

2. Use the --version option to find out which version you are running.

$ bash --version | head -1 | awk '{print$4}'
4.4.20(1)-release

3. Which shell configuration files are read when you login to your system using the graphical user interface and then opening a terminal window?

When you login in GUI you don't get shell, instead you get session manager or window manager.

The following file read because you are opening non-login interactive shell :

~/.bashrc

4. Are the following shells interactive shells? Are they login shells?

Interactive means you can enter commands.
Login shell means that you got the shell after authenticating to the system, usually by giving your user name and password.

Good explanation with examples

-A shell opened by clicking on the background of your graphical desktop, selecting "Terminal" or such from a menu.

Interactive, non-login

-A shell that you get after issuing the command ssh localhost.

Interactive, login

-A shell that you get when logging in to the console in text mode.

Interactive, login

-A shell obtained by the command xterm &.

Interactive, non-login

-A shell opened by the mysystem.sh script.

Non-interactive, non-login

-A shell that you get on a remote host, for which you didn't have to give the login and/or password because you use SSH and maybe SSH keys.

Interactive, login

5. Can you explain why bash does not exit when you type Ctrl+C on the command line?

Ctrl+C is the interrupt signal. Terminal window is interactive shell not the process.

6. Display directory stack content

The directory stack is a list of directories you have previously navigated to.

~$ echo $DIRSTACK
~

Working with the directory stack in linux

7. If it is not yet the case, set your prompt so that it displays your location in the file system hierarchy, for instance add this line to ~/.bashrc:

export PS1="\u@\h \w> "

8. Display hashed commands for your current shell session.

$ hash
hits	command
   1	/usr/bin/vim
   1	/usr/bin/w
   3	/bin/ls

9. How many processes are currently running on your system? Use ps and wc, the first line of output of ps is not a process!

$ ps aufxS | tail -n +2 | wc -l
319

10. How to display the system hostname? Only the name, nothing more!

hostname

2.5 Exercises

Script that display the path to your homedirectory and the terminal type that you are using. Additionally it shows all the services started up in runlevel 3 on your system.

Adding the execute permissions :

chmod +x script1.sh

Run in the debug mode :

bash -x script1.sh