date command formatThe prompt of Bash can be customized, and can displays several useful informations.
The main prompt is stored in the PS1 variable of the shell. You can show it with the following command:
echo $PS1
and you can change it by modifying the content of this variable. For example this command will change your prompt:
PS1="This is my new prompt >>> "
If you close your terminal and open it again, the prompt is reverted to the default ; that is normal because you have not
save it. For permanently changing you prompt, you have to modify your ~/.bashrc file. The simple way to change your
prompt is to add the following line at the end of the file:
PS1="Prompt >>> "
Now let's see the different things that can be displayed in the prompt…
Prompt Helper is a Javascript script that helps you to customize your prompt by displaying your modification in real time. It does not support all the features of a shell, but it is sufficient for doing what we want to.
| Sequence | description | Example/Preview |
|---|---|---|
| \d | The date (+%a\ %b\ %d format) 1) | Mon Jun 13 |
| \D{format} | The date in the desired format (in strftime format) 2) | |
| \t | The time, 24-hour (+%k:%M:%S format) 3) | 22:42:01 |
| \T | The time, 12-hour (+%l:%M:%S format) 4) | 10:42:01 |
| \@ | The time, 12-hour, with AM/PM (+%l:%M\ %p format) 5) | 10:42 PM or 10:42 |
| \A | The time, 24-hour (+%k:%M format) 6) | 22:42 |
| \h | The host name | hostname |
| \H | The full host name (with the domain name) | hostname.domain |
| \j | The number of suspended processes in the current shell (<Ctrl>+Z) | 0 |
| \l | The name of the shell's terminal device | tty1 or 1 |
| \s | The name of the shell executable | bash |
| \u | The current user name | username |
| \v | The version of the shell (short) | 4.1 |
| \V | The version of the shell (with the patch level) | 4.1.5 |
| \w | The path of the working directory | ~/Documents or /usr/bin |
| \W | The name of the working directory | Documents or bin |
| \! | The current command number in the history | 538 |
| \# | The command number (from the start of the shell) | 42 |
| \$ | If the current user is root, displays a #, else displays a $ | $ or # |
| \[ | Start a sequence of non-printing characters | |
| \] | End a sequence of non-printing characters | |
| \a \007 | The ASCII bell character | |
| \n | Start a new line | |
| \r | Carriage return | |
\\ | A single backslash | \ |
| \e \033 | The ASCII Escape character. Used by some Control Sequences (see bellow) |
Here we will see only a part of the formating and color sequences. For using colors in your shell you can
use sequences like “\e[Attrm”. Attr can
be replaced by one or more attributes (see bellow).
E.g.:
\e[31mRed Text
\e[42mGreen background
\e[1mBold text
\e[1;31;42mBold and Red text, Green background
| Black | Red | Green | Yellow | Blue | Magenta | Cyan | White | Default color | |
|---|---|---|---|---|---|---|---|---|---|
| Foreground | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 39 |
| Background | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 49 |
Fore more information about colors see: colors.
| Bold | Underlined | Inverted | Default formating and color |
|---|---|---|---|
| 1 | 4 | 7 | 0 |
Fore more information about formatting see: formatting.
Debian default prompt (no color):
${debian_chroot:+($debian_chroot)}\u@\h:\w\$
Debian default colored prompt:
${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$
Demo 1:
\[\e]0;[\w]\a\r\e[1;38;5;118;48;5;16m\] \u \[\e[38;5;16;48;5;118m\] \h \[\e[0m\] \$
Demo 2:
\n\[\e[0;38;5;118m\]┏━━━━┫\[\e[1;48;5;118;1;38;5;16m\] \u@\h \[\e[0;38;5;118m\]┣━━┫\[\e[1;48;5;118;1;38;5;16m\] \W \[\e[0;38;5;118m\]┣━━━━━\n┃\n┗━━\$❱\[\e[0m\]
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