Aqui está uma explicação simples sobre o prompt env vars (extraído da página man bash):
PS0 – The value of this parameter is expanded like PS1 and displayed
by interactive shells after reading a command and before the command
is executed.
PS1 – The value of this parameter is expanded (see
PROMPTING below) and used as the primary prompt string. The default
value is \s-\v\$ .
PS2 – The value of this parameter is expanded as
with PS1 and used as the secondary prompt string. The default is >
PS3 – The value of this parameter is used as the prompt for the select
command
PS4 – The value of this parameter is expanded as with PS1 and
the value is printed before each command bash displays during an
execution trace. The first character of PS4 is replicated multiple
times, as necessary, to indicate multiple levels of indirection. The
default is +
e aqui algumas variantes que você pode usar no seu formato:
\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
\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
Então: um exemplo simples
PS1= "\h:\! \w \$"
Espero que ajude
Mais informações, você pode ver a página homem