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rlwrap(1) General Commands Manual rlwrap(1)

NAME
rlwrap - readline wrapper

SYNOPSIS
rlwrap [rlwrap-options] command ...

DESCRIPTION
rlwrap runs the specified command, intercepting user input in order to pro-
vide readline's line editing, persistent history and completion.

rlwrap tries (and almost succeeds) to be completely transparent - you (or
your shell) shouldn't notice any difference between command and rlwrap com-
mand - except the added readline functionality, of course. This should
even hold true when you are re-directing, piping and sending signals from
and to command, and when command manipulates its terminal settings, working
directory or (with the -U option) command line.

There are many options to add (programmable) completion, handle multi-line
input, colour and re-write prompts. If you don't need them (and you proba-
bly don't), you can skip the rest of this manpage, although some of those
options could make your command line quite a bit more comfortable...

OPTIONS
-a[password_prompt], --always-readline[=password_prompt]
Always remain in "readline mode" (see below), regardless of com-
mand's terminal settings. If rlwrap "does nothing" this is the op-
tion to use, as command is apparently already doing its own line
editing. NB: With this option, rlwrap will echo (and save) pass-
words, unless you give command's password prompt as an argument.

The argument is optional; if given, it has to directly follow a
short option without an intervening space (-aPassword:) and a long
option with an equals sign (--always-readline=Password:).

The -N (--no-children) option can be used to avoid wrapping pagers
and editors called from command; this should make them much more us-
able

-A[!], --ansi-colour-aware[=!]
Prompts that use colour, or use other CSI codes to e.g. set window
titles or enable bracketed-paste will confuse rlwrap, especially at
the end of long input lines. This option will usually (but by no
means always) make rlwrap better behaved in such cases.

Giving '!' as an argument will make rlwrap remove all color codes
from the prompt.

The argument is optional; if given, it has to directly follow a
short option without an intervening space (-A!) and a long option
with an equals sign (--ansi-colour-aware=!).

-b, --break-chars list_of_characters
Consider the specified characters word-breaking (whitespace is al-
ways word-breaking). This determines what is considered a "word",
both when completing and when building a completion word list from
files specified by -f options following (not preceding!) it. De-
fault list (){}[],'+-=&^%$#@";|\ Unless -c is specified, / and .
(period) are included in the default list.

-c, --complete-filenames
Complete filenames (filename completion is always case-sensitive,
even with the -i option). On Linux, OS X, FreeBSD and Solaris rlwrap
will keep track of command's working directory, so that relative
filenames will be completed as one would expect.

-C, --command-name command_name|N
Use command_name instead of command to determine the names of his-
tory and completion files, and to initialise readline (as specified
in ~/.inputrc). A numeric argument N > 0 means: use the Nth argument
counting backwards from the end of the argument list

-D, --history-no-dupes n
How aggressively to weed out duplicate entries from the input his-
tory. If n = 0, all inputs are kept in the history list, if n = 1
(this is the default) consecutive duplicates are dropped from the
list, while n = 2 will make rlwrap drop all previous occurrences of
the current input from the list.

-e, --extra-char-after-completion char
By default, rlwrap appends a space after any inserted completion
text. Use this option to change this to '' (don't insert anything)
or some other character.

-E, --always-echo
By default, rlwrap avoids displaying passwords by echoing '***'
whenever the client clears the ECHO flag on its input. This option
will make rlwrap ignore this ECHO flag and always echo the user's
input. (-aPassword: will still work as expected)

-f, --file file
Split file into words (using the default word-breaking characters,
or those specified by --break-chars), and add them to the completion
word list. This option can be given more than once, and adds to the
default completion list in $RLWRAP_HOME or /usr/local/share/rl-
wrap/completions.

Specifying -f . will make rlwrap use the current history file as a
completion word list.

-g, --forget-matching regexp
Forget (i.e. never put into the history list) input lines that match
the POSIX 1003.2 regular expression regexp. The match is always
case-insensitive. perl-style character classes like '\d' are not
recognised, use '[:digit:]'. For more about regular expressions, see
regex (7)

-h, --help
Print a short help message.

-H, --history-filename file
Read command history from file (and write it back there if --hist-
size >= 0)

-i, --case-insensitive
Ignore case when completing (filename completion remains case-sensi-
tive). This option has to come before any -f options.

-I, --pass-sigint-as-sigterm
Send a TERM signal to command when an INT is received (e.g. when you
press CTRL-C).

-l, --logfile file
When in readline mode, append command's output (including echo'ed
user input) to file (creating file when it doesn't exist).

-m[newline_substitute], --multi-line[=newline_substitute]
Enable multi-line input using a "newline substitute" character se-
quence (" \ ", [space-backslash-space] by default). Newline substi-
tutes are translated to newlines before sending the input to com-
mand. With this option, you can call an external editor $RLWRAP_EDI-
TOR on the (expanded) current input with the rlwrap_call_editor key
(CTRL-^ by default) The argument is optional; if given, it has to
directly follow a short option without an intervening space (-m';;')
and a long option with an equals sign (--multi-line=';;').

-M, --multi-line-ext .ext
Call multi-line-editor on temporary files with filename extension
.ext (useful for e.g. automatic syntax colouring)

-n, --no-warnings
Don't print warnings.

-N, --no-children
When rlwrap is invoked with the --always-readline option, editors
and pagers that are called by the client will be pretty unusable, as
they will see your keypresses only if you press ENTER. rlwrap -N
will avoid this problem by switching to direct mode if it thinks
command is waiting for one of its children.

-o, --one-shot
Send an EOF to command after accepting the first line of input

-O, --only-cook regexp
Only ever "cook" prompts that match regexp, which can be preceded by
'!', meaning that all matching candidate prompts will be cooked im-
mediately ("confident mode").

-p[colour], --prompt-colour[=colour]
Use one of the colour names black, red, green, yellow, blue, cyan,
purple (=magenta) or white, or an ANSI-conformant <colour_spec> to
colour any prompt displayed by command. An uppercase colour name
(Yellow or YELLOW ) gives a bold prompt. Prompts that already con-
tain (colour) escape sequences or one of the readline "ignore mark-
ers" (ASCII 0x01 and 0x02) are not coloured. This option implies
--ansi-colour-aware. You can also use a colour spec of the form
<attr>;<fg>[;<bg>], for example -p'1;31' will give a bold red
prompt on the current background (this is the default when no argu-
ment is given). Google for 'ANSI color' to learn more about colour
codes. The argument is optional; if given, it has to directly fol-
low a short option without an intervening space (-p'Red') and a long
option with an equals sign (--prompt-colour='Red').

-P, --pre-given text
Start rlwrap with text in its edit buffer (this will automatically
set the --always-readline option).

-q, --quote-characters list_of_characters
Assume that the given characters act as quotes, e.g. when matching
parentheses. Take care to escape the list properly for your shell
(example: -q "\"'", which happens to be the default, or -q "\""
which will be better for lisp-like input)

-r, --remember
Put all words seen on in- and output on the completion list.

-R, --renice
Make rlwrap nicer than command (cf nice (1)). This may prevent rl-
wrap from interrupting command to display a prompt when command is
still "thinking" about what to output next.

-s, --histsize N
Limit the history list to N entries, truncating the history file
(default: 300). A negative size -N (even -0) means the same as N,
but treats the history file as read-only.

-S, --substitute-prompt prompt
Substitute the specified prompt for command's own prompt. Mainly
useful when command doesn't have a prompt.

-t, --set-term-name name
Set command's TERM to name. Programs that confuse rlwrap with fancy
screen control codes can sometimes be tamed by specifying -t dumb

-U, --mirror-arguments
(linux only) Keep track of command's arguments as seen by the ps (1)
command, and mirror them in rlwrap's own arguments This can be use-
ful for commands that overwrite command-line password arguments that
would be exposed by rlwrap without this option. The mirroring takes
place after the first user input, or every few milliseconds, if you
use the --polling option.

-v, --version
Print rlwrap version.

-w, --wait-before-prompt timeout
In order to determine if command's last output is a prompt, rlwrap
waits timeout milliseconds after receiving it. Only when no more
output has arrived, it is cooked (coloured, filtered and/or replaced
by a substitute prompt) and displayed as a prompt. Before this the
prompt is displayed "uncooked". Most users won't notice, but heavy
cookers can prepend the timeout with a minus sign, making rlwrap
hold back the prompt until it has been cooked ("patient mode"). This
will prevent flashing of the prompt, but it will also interfere with
long output lines and make switches from direct to readline mode
less reliable. Default timeout: 40 ms

-W, --polling
EXPERIMENTAL: Wake up every timeout millisecs, where timeout is the
same as for the -w (--wait-before-prompt) option, 40 ms by default.
This is used to sense the slave's interrupt character and ISIG flag
and to adjust stdin's terminal settings accordingly, even before you
press a key. Try this option e.g. when CTRL-C acts differently on
command with, and without, rlwrap.

-z, --filter some_filter
Use some_filter to change rlwrap's behaviour. Filters can be used to
keep certain input out of the history, to change the prompt, to im-
plement simple macros, programmable hotkeys for e.g. fuzzy history
search, and programmable completion. rlwrap comes with a perl and a
python module to make filter writing easy. (cf. RlwrapFilter(3pm)
for the perl module, the python one is very similar) A number of ex-
ample filters are installed in the directory /usr/local/share/rl-
wrap/filters.

rlwrap -z listing

lists all currently installed filters, while

rlwrap -z some_filter

displays information about some_filter

If some_filter needs arguments, you should quote the whole filter
command line:

rlwrap -z 'some_filter args' command ...
rlwrap -z 'pipeline filter1 ... : filter2 ... : ...' command ...

If this command line contains shell metacharacters, rlwrap passes it
to the system shell for parsing.

As filters have to follow a special protocol, shell commands like
sed and grep cannot be used as rwlrap filters. They can, however, be
converted into filters by the makefilter filter:

rlwrap -z 'makefilter egrep -i --color "error|$"' command

will color all occurrences of "error" (or "Error") in command's
output, while

rlwrap -z 'makefilter --message-type history sed -e
s"/whisky/lemonade/"' command

sanitises your drinking history. Both filters can be combined using
the pipeline filter, of course.

EXAMPLES
Run nc (netcat) with command-line editing and history
rlwrap nc

Wrap smbclient (which uses readline itself), keep passwords out of the his-
tory and don't interfere with pagers (like less) called by smbclient.
rlwrap -aPassword: -N smbclient //PEANUT/C

Wrap sensitive_app, hide password from ps (if sensitive_app does so) and
keep all input that starts with a space out of history:
rlwrap -g '^ ' -U sensitive_app --password MySeCrEt

Wrap gauche (a Scheme interpreter) with a bold blue prompt, enable
multi-line editing (using .scm as filename extension) and don't consider
single quotes as quotes (so that the parentheses in e.g. (print 'q) match)
rlwrap -pBlue -m -M .scm -q'"' gosh

Wrap sqlite3, use the pipeto filter to be able to pipe the output of SQL
commands through grep and/or less, complete (case-insensitively) on the SQL
keywords in 'sql_words'
rlwrap -a -z pipeto -i -f sql_words sqlite3 contacts.db

In a shell script, use rlwrap in 'one-shot' mode as a replacement for read
order=$(rlwrap -pYellow -S 'Your pizza? ' -H past_or-
ders -P Margherita -o cat)

DIRECT MODE AND READLINE MODE
Most simple console commands put your terminal either in "cooked" or in
"raw" mode. In cooked mode the terminal will wait until you press the ENTER
key before handing the entire line to the program, in raw mode every key
you press is handed down immediately. In cooked mode you generally can use
the backspace key, but not the arrow keys, to edit your input.

When you rlwrap command, rlwrap will run it a in a separate session, under
its own (controlling) "pseudo-terminal" (pty), and monitor this pty to see
whether it is in raw, or in cooked mode. In the first case, rlwrap will
copy all input and output directly between command and your terminal ("di-
rect mode"). In the second case, rlwrap will use readline to edit your in-
put ("readline mode"), and monitor command's output - every last line that
doesn't end with a newline is a potential prompt. How it handles such a
candidate prompt depends on its being in "patient" or "impatient" mode, see
below.

Simple console commands use cooked mode whenever they want whole input
lines, and raw mode when they want single keypresses. Those are the progams
for which rlwrap is most useful. More sophisticated commands have their
own line editor and hence use raw mode all the time. With those commands,
rlwrap will appear to "do nothing". Therefore, if rlwrap is in direct mode
when the user presses ENTER for the first time it will give a warning that
it needs --always-readline to do anything at all (warnings can be sup-
pressed with the -n option)

PATIENT, IMPATIENT AND CONFIDENT MODE
If command writes a lot of output, it tends to be written (and read) in
"chunks". Not all chunks will end with a newline, and we need to distin-
guish their last lines ("candidate prompts") from real prompts, especially
if we want to re-write ("cook") prompts. rlwrap solves this (almost) by
waiting a little, to see if there is more to come. "A little" is 40 msec by
default, but this can be changed with the -w option. Normally rlwrap
writes the candidate prompt as soon as it is received, replacing it with a
"cooked" version after the wait time. This is called "impatient" mode. If
you don't like the flashing effect (which can become annoying when you
"cook" the prompt heavily) you can put rlwrap in "patient mode" by specify-
ing a negative value with -w (e.g. -w -40). Rlwrap will then hold back the
prompt and only print if after cooking. If prompts always match some regu-
lar expression you can specify "confident mode" with --only-cook='!<reg-
exp>' (note the exclamation mark). Then all candidate prompts that match
(and only those) will be cooked immediately. They will, however, not be
"uncooked" if more output arrives, which can happen if they weren't prompts
after all. Confident mode doesn't work with a negative value for the -w
option.

COOKING PROMPTS
If and when rlwrap decides that it has a prompt, it will perform a number
of actions on it, depending on the given options: filtering (-z), substi-
tuting (-S) and colouring (-p), in this order. The resulting "cooked"
prompt is then printed (after erasing the "raw" prompt, if necessary)

SPECIAL KEYS AND BINDABLE COMMANDS
Control + O
Accept the current line, but don't put it in the history list. This
action has a readline command name rlwrap-accept-line-and-forget

Control + ^
Use an external editor (see RLWRAP_EDITOR below) to edit the current
input (this will only work if the -m option is set). This action has
a readline command name rlwrap-call-editor

(Not currently bound)
Any key (or key sequence, see below) can be bound to the readline
command rlwrap-direct-keypress. This key (or keys) will then always
be sent directly to command, even when rlwrap is not in direct mode.

(Not currently bound)
Any key or key combination can be bound to the readline command rl-
wrap-direct-prefix. This makes it possible to define multi-key di-
rect keypresses by defining their first key(s) as a 'direct prefix'

(Not currently bound)
Any key can be bound to the readline command rlwrap-hotkey. This key
will then cause the current input line and the current history to be
filtered (cf. RlwrapFilter(3pm)) through the current filter (hence
be a no-op when there is no filter), which then can re-write the in-
put line, move the cursor and update the history. After that, the
user can still edit the resulting input.

(Not currently bound)
rlwrap-hotkey-without-history acts like rlwrap-hotkey, but the his-
tory (which can be quite large) is not passed to the filter. This is
more efficient if the filter wouldn't do anything useful with the
history anyway.

The special keys were chosen for no other reason than that they are not
currently bound to any readline action. If you don't like them, (or your
window manager swallows them) they (and the other 4 commands) can be
re-bound more sensibly by including lines like the following in your ~/.in-
putrc:

"\M-\C-m": rlwrap-accept-line-and-forget # ESC-ENTER to accept but keep out of history
"\C-x": rlwrap-call-editor # CTRL-x e to edit (multi-line) input in editor of your choice
$if erl # (only) for the Erlang shell:
"\C-g": rlwrap-direct-keypress # pass CTRL-g directly to enter 'user switch' command
$endif
"\C-t": rlwrap-direct-prefix # make it possible to define direct keypresses that start with CTRL-t ...
"\C-tx": rlwrap-direct-keypress # ... in that case: pass CTRL-t + x directly.
"\C-y": rlwrap-hotkey-without-history # CTRL-y to filter input line (and e.g. insert X selection)

cf. the readline(3) manpage. (NB: take care to not use keys that are al-
ready caught by your window manager, or by the terminal driver, like
CTRL+S, as rlwrap will never see those)

ENVIRONMENT
RLWRAP_HOME:
directory in which the history and completion files are kept.

RLWRAP_EDITOR (or else EDITOR, or else VISUAL):
editor to use for multi-line input (and rlwrap-edit-history). Exam-
ple:

export RLWRAP_EDITOR="vi +%L"
export RLWRAP_EDITOR="vim '+call cursor(%L,%C)'"
export RLWRAP_EDITOR="emacs +%L:%C %F"

The first example above is the default; %L and %C are replaced by line and
column numbers corresponding to the cursor position in rlwrap's edit
buffer, %F is replaced by name of the (temporary) file. If %F is not used,
this name is put after the (expanded) $RLWAP_EDITOR

RLWRAP_FILTERDIR:
Any executable along your PATH can in theory be used as a filter,
but because filters have to follow a rather outlandish protocol (cf.
RlwrapFilter (3)) it is a good idea to keep them separate. This is
why rlwrap adds a special filter directory in front of $PATH just
before launching a filter. By default, this is /usr/local/share/rl-
wrap/filters, but $RLWRAP_FILTERDIR is used instead, if set.

SIGNALS
A number of signals are forwarded to command: HUP INT QUIT USR1 USR2 TERM
and (by way of resizing command's terminal) WINCH. Some care is taken to
handle TSTP (usually a result of a CTRL-Z from the terminal) sensibly - for
example, after suspending rlwrap in the middle of a line edit, continuing
(by typing 'fg') will land you at the exact spot where you suspended it.

A filter can be used to modify/ignore signals, or send output "out of band"
to the rlwrapped command.

Filters (except those that filter signals) that take more than 1 second to
respond can be interrupted by a CTRL-C from the terminal (although rlwrap
will not survive this)

If command changes the keystrokes that send a particular signal from the
keyboard (like emacs, which uses CTRL-G instead of CTRL-C) rlwrap will do
the same (but only after the next keystroke - use the --polling option to
make rlwrap more transparent in this respect)

When command is killed by a signal, rlwrap will clean up, reset its signal
handlers an then commit suicide by sending the same signal to itself. This
means that your shell sees the same exit status as it would have seen with-
out rlwrap.

REDIRECTION
When the standard input is not a terminal (or when run inside an emacs
buffer), editing input doesn't make sense, so rlwrap will ignore all op-
tions and simply execute command in place of itself. When stdout (or
stderr) is not a terminal, rlwrap will re-open it to /dev/tty (the users
terminal) after it has started command, so that command's output is redi-
rected as expected, but keyboard input and rlwrap error messages are still
visible.

The upshot of this is that rlwrap command behaves more or less like command
when redirecting.

EXIT STATUS
non-zero after a rlwrap error, or else command's exit status. rlwrap will
always leave the terminal in a tidy state, even after a crash.

FILES
rlwrap expects its history and completion files in $RLWRAP_HOME, but uses
.dotfiles in the user's home directory if this variable is not set. This
will quickly become messy if you use rlwrap for many different commands.

$RLWRAP_HOME/command_history, ~/.command_history
History for command (remember that command may be overridden by the
--command-name (or -C) option)

$RLWRAP_HOME/command_completions, ~/.command_completions
Per-user completion word list for command. rlwrap never writes into
this list, but one can use -l logfile and then -f logfile to simu-
late the effect of a -r option that works across invocations.

/usr/local/share/rlwrap/completions/command
System-wide completion word list for command. This file is only con-
sulted if the per-user completion word list is not found.

$INPUTRC, ~/.inputrc
Individual readline initialisation file (See readline (3) for its
format). rlwrap sets its application name to command (this can be
overridden by the -C option), enabling different behaviours for dif-
ferent commands. One could e.g. put the following lines in ~/.inpu-
trc:

$if coqtop
set show-all-if-ambiguous On
$endif

making rlwrap show all completions whenever it runs coqtop

BUGS and LIMITATIONS
Though it is flexible, delivers the goods (readline functionality), and ad-
heres to the Unix "many small tools" paradigm, rlwrap is a kludge. It
doesn'tknow anything about command's internal state, which makes con-
text-sensitive completion impossible. Using the GNU Readline library from
within command is still by far the best option.

Also, as "it takes two to tango" there is no way for rlwrap to synchronise
its internal state with command, resulting in a number of subtle race con-
ditions, where e.g. command may have changed the state of its terminal be-
fore rlwrap has read command output that was written before the state
change. You will notice these races especially on a busy machine and with
heavy "cooking" and filtering, when suddenly (and unpredictably) prompts or
command output are garbled or incorrectly coloured.

rlwrap can try, but often fails to, handle prompts that contain control
characters (prompts, and the effect of -A and -t, can be analysed by the
filter dissect_prompt). If -A (--ansi-colour-aware) doesn't help, a filter
may be needed to clean up the prompt. Specifying --set-term-name with a
simpler, of even dumb, terminal may also help.

VERSION
This manpage documents rlwrap version 0.45.2

AUTHORS
The GNU Readline library (written by Brian Fox and Chet Ramey) does all the
hard work behind the scenes, the pty-handling code (written by Geoff C.
Wing) was taken practically unchanged from rxvt, and completion word lists
are managed by Damian Ivereigh's libredblack library. The rest was written
by Hans Lub (hanslub42@gmail.com).

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