Exercise: Find your way around

Find your way around

• Move around with absolute and relative paths, ., .. and ~.
• Read long listings and find hidden files.
• Recognise a directory you may not enter.

Start the exercise

On workstation, start the exercise. It removes any practice files from an earlier run from student's home on servera.

[student@workstation ~]$ lab start sa-navigate

Later tasks assume that you are logged in to the server they name: ssh student@servera from workstation, then sudo -i for a root shell.

Log in to servera and see where you start

[student@workstation ~]$ ssh student@servera
[student@servera ~]$ pwd
/home/student

Find your hidden files

Plain ls shows nothing, but your home directory isn't empty:

[student@servera ~]$ ls
[student@servera ~]$ ls -a
.  ..  .bash_history  .bash_logout  .bash_profile  .bashrc  .ssh

.bashrc holds your shell settings and .ssh your SSH files. Every new account gets the dotfiles from /etc/skel, a template directory; check with ls -a /etc/skel. (.bash_history appears once you have logged in interactively.)

Visit /etc with an absolute path

[student@servera ~]$ cd /etc
[student@servera etc]$ ls -l hostname
-rw-r--r--. 1 root root 24 Oct  3 09:28 hostname
[student@servera etc]$ ls -ld .
drwxr-xr-x. 79 root root 4096 Oct  3 09:29 .

hostname is a relative path here, short for /etc/hostname. ls -ld . describes the current directory itself rather than its contents: owned by root, and a d for directory.

Go down, up and sideways

Use the full path once, then relative paths:

[student@servera etc]$ cd /usr/share/doc/bash
[student@servera bash]$ ls
bash.html  bashref.html  FAQ  INTRO  RBASH  README
[student@servera bash]$ cd ../../..
[student@servera usr]$ pwd
/usr
[student@servera usr]$ cd ../etc
[student@servera etc]$ pwd
/etc

Three .. steps climb from /usr/share/doc/bash to /usr; ../etc then goes up to / and down into etc.

Jump back and forth, then go home

[student@servera etc]$ cd /var/log
[student@servera log]$ cd -
/etc
[student@servera etc]$ cd -
/var/log
[student@servera log]$ cd
[student@servera ~]$

Try to enter root's home directory

~root is root's home, /root. Ordinary users may not look inside it:

[student@servera ~]$ cd ~root
-bash: cd: /root: Permission denied
[student@servera ~]$ ls -l ~root
ls: cannot open directory '/root': Permission denied

The directory is there; its permissions keep you out. Chapter 7 shows how to read why.

Create practice files with touch, and log out

[student@servera ~]$ touch plan.txt "team notes.txt"
[student@servera ~]$ ls -l
total 0
-rw-r--r--. 1 student student 0 Oct  3 09:58  plan.txt
-rw-r--r--. 1 student student 0 Oct  3 09:58 'team notes.txt'
[student@servera ~]$ exit

The quotes keep team notes.txt as one name, and ls shows it quoted for the same reason, so you could copy it into a command as it is. The next lesson shows how to remove files. To put servera back as it was, run rht-vmctl reset servera on the Ubuntu host.

Grade and finish

Check your work with lab grade sa-navigate, then put the exercise away with lab finish sa-navigate.