The first thing you got to ask yourself, of course, is whether you need the computer name, also called "hostname", in your command prompt or not. That's important if you are logging in to other systems remotely, rarely done by the average desktop user. If the answer to that question is 'yes' but you want to change the hostname to something more nice or appropriate, or you want to change it for some other reason, you just need to change two entries in two different configuration files, as shown below.
Notice the allowed characters for setting a hostname, otherwise you can easily end up with a broken system variable, with all sorts of possible issues!:
Host names may contain only alphanumeric characters, minus signs ("-"), and periods ("."). They must begin with an alphabetic character and end with an alphanumeric character.
Source: http://manpages.ubuntu.com/manpages/oneiric/en/man5/hosts.5.html
Open the concerning files with either of these commands. You will easily spot your currently set hostname; then just change it to your liking.
gksudo gedit /etc/hostname
gksudo gedit /etc/hosts
The default file contents look like these:
krytarik-desktop
127.0.0.1 localhost 127.0.1.1 krytarik-desktop # The following lines are desirable for IPv6 capable hosts ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters ff02::3 ip6-allhosts
Depending on the Ubuntu version, there are different behaviors that can occur when editing those files. Particularly, when the changes are being applied, possibly messing up the "/etc/hosts" during the process; and the implications on the running desktop environment. But we are surely on the safe side when I advise to:
- Load both the concerning files in a text editor at the same time (whether it's on the CLI or GUI), and save them after another, twice, alternately - ignoring any possible upcoming warnings about intermittent changes, as that's exactly what we want to override.
- Re-check your "/etc/hosts" after editing both files, and after either running the below command or a reboot.
- Either run this command to reload the hostname from the just edited file and apply it to your system immediately (thanks to Yetiman64 for this tip in the comments!), and if you notice any issues, relogin:
sudo hostname -F /etc/hostnameThis has the bonus that it would output an error message if the newly chosen hostname is invalid, so I in fact recommend that. - Or, alternatively, just reboot.
Regardless of what Linux distribution you are running, to change the command prompt, you always need to change the settings for the "PS1" variable in the file ".bashrc" located in your home directory, as long as you are using the Bash, of course, not the Shell.
This is how to change the command prompt in Ubuntu, and presumably any other Debian-based Linux distro, judging from it being literally included in the code.
if [ "$color_prompt" = yes ]; then
PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
else
PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
# PS1='${debian_chroot:+($debian_chroot)}[\u]:\w\$ '
fi
unset color_prompt force_color_prompt
# If this is an xterm set the title to user@host:dir
case "$TERM" in
xterm*|rxvt*)
PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
# PS1="\[\e]0;${debian_chroot:+($debian_chroot)}[\u]: \w\a\]$PS1"
;;
*)
;;
esacIf you are running a non-Debian-based Linux distro, you'll obviously find other settings for "PS1" in the ".bashrc", but they should be similarly set up and easy to change. But if you don't find any settings for it in there, you can simply set them up yourself, derived from the code above.
To build up the command prompt, you have quite a range of keys available, each of which either pulls in some kind of data or just formats the command prompt. This is from 'bash's manpage:
PROMPTING
When executing interactively, bash displays the primary prompt PS1 when
it is ready to read a command, and the secondary prompt PS2 when it
needs more input to complete a command. Bash allows these prompt
strings to be customized by inserting a number of backslash-escaped
special characters that are decoded as follows:
\a an ASCII bell character (07)
\d the date in "Weekday Month Date" format (e.g., "Tue May
26")
\D{format}
the format is passed to strftime(3) and the result is
inserted into the prompt string; an empty format results
in a locale-specific time representation. The braces are
required
\e an ASCII escape character (033)
\h the hostname up to the first `.'
\H the hostname
\j the number of jobs currently managed by the shell
\l the basename of the shell's terminal device name
\n newline
\r carriage return
\s the name of the shell, the basename of $0 (the portion
following the final slash)
\t the current time in 24-hour HH:MM:SS format
\T the current time in 12-hour HH:MM:SS format
\@ the current time in 12-hour am/pm format
\A the current time in 24-hour HH:MM format
\u the username of the current user
\v the version of bash (e.g., 2.00)
\V the release of bash, version + patch level (e.g., 2.00.0)
\w the current working directory, with $HOME abbreviated
with a tilde (uses the value of the PROMPT_DIRTRIM vari‐
able)
\W the basename of the current working directory, with $HOME
abbreviated with a tilde
\! the history number of this command
\# the command number of this command
\$ if the effective UID is 0, a #, otherwise a $
\nnn the character corresponding to the octal number nnn
\\ a backslash
\[ begin a sequence of non-printing characters, which could
be used to embed a terminal control sequence into the
prompt
\] end a sequence of non-printing characters
The command number and the history number are usually different: the
history number of a command is its position in the history list, which
may include commands restored from the history file (see HISTORY
below), while the command number is the position in the sequence of
commands executed during the current shell session. After the string
is decoded, it is expanded via parameter expansion, command substitu‐
tion, arithmetic expansion, and quote removal, subject to the value of
the promptvars shell option (see the description of the shopt command
under SHELL BUILTIN COMMANDS below).Source: http://manpages.ubuntu.com/manpages/oneiric/en/man1/bash.1.html
