Introduce new prompt format characters:
- '\[' starts the sequence of non-printing chatacters
- '\]' ends the sequence of non-printing characters
Within these sequences, the following characters are now supported:
- '\a' emits ASCII BEL (0x07, 007) character
- '\e' emits ASCII ESC (0x1b, 033) character
- '\r' emits ASCII CR (0x0d, 015) character
- '\n' emits ASCII CRLF sequence
These can be used to embed ANSI sequences into prompt strings.
Example in .shrc:
PS1="\[\e[7m\]\u@\h\[\e[0m\]:\w \\$ "
This tries to maintain some degree of compatibility with GNU bash,
that uses GNU readline library (which behaves slightly different from
BSD editline): It has two "non-printing boundary" characters:
- RL_PROMPT_START_IGNORE (\001)
- RL_PROMPT_END_IGNORE (\002)
while BSD editline only has one (when using EL_PROMPT_ESC setting), so
for this purpose, ASCII \001 was chosen and both \[ and \] emits
this character.
And while here, enlarge PROMPTLEN from 128 to 192 characters.
Reviewed by: jilles
Approved by: jilles
Differential Revision: https://reviews.freebsd.org/D37701
3cf65f8a7f