UNIX Escape Sequence
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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 in the table below.
To test your terminal for the usage of the escape sequence try the following:
echo -en "\033[7A\033[1;35m BASH \033[7B\033[6D"
This should move the cursor seven lines up screen, print the word " BASH ", and then return to where it started to produce a normal prompt.
| Char | Description |
|---|---|
| \a | ASCII bell character (07) |
| \d | The date in "Weekday Month Date" format (e.g., "Tue May 26") |
| \e | ASCII escape character (033) |
| \h | Hostname up to the first `.' |
| \H | Hostname |
| \j | 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 |
| \u | the username of the current user |
| \v | the version of bash (e.g., 2.00) |
| \V | the release of bash, version + patchlevel (e.g., 2.00.0) |
| \w | the current working directory |
| \W | the basename of the current working directory |
| \! | 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 character |
See also
- Bash Prompt Howto with examples (tip).
- Steve Parker Escape Characters
- ANSI escape sequences to produce color in UNIX.
