rlwrap v 0.46 October 2022
WHAT IT IS:
rlwrap is a 'readline wrapper', a small utility that uses the GNU
Readline
library to allow the editing of keyboard input for any command.
I couldn't find anything like it when I needed it, so I wrote this one
back in 1999. By now, there are (and, in hindsight, even then there
were) a number of good readline wrappers around, like rlfe,
distributed as part of the GNU readline library, and the amazing
socat.
You should consider using rlwrap especially when you need
user-defined completion (by way of completion word lists) and
persistent history, or if you want to program 'special effects' using
the filter mechanism.
As it is often used with older or even obsolete software, rlwrap
strives to compile and run on a fairly wide range of not necessarily
recent Unix-like systems (FreeBSD, OSX, HP-UX, AIX, Solaris, QNX,
cygwin, linux and probably quite a few more) This would not have been
without Polarhome's now retired 'dinosaur zoo'
of ageing Unix systems
HOW TO USE IT:
If
$ <command> <args>
displays the infamous ^[[D when you press a left arrow key, or if
you just want decent input history and completion, try:
$ rlwrap [-options] <command> <args>
You should not notice any difference compared to directly calling <command> <args>, except that you now can edit <command>'s input and recall
its entire input history using the arrow keys.
Input history is remembered accross invocations, separately for
different <command>s. CTRL-R will search the input
history, like in bash. With the -r and -f options you can specify the list of
words which rlwrap will use as possible completions, taking them
from a file (-f option) or from <command>'s past in/output (-r
option).
rlwrap continually monitors <command>'s terminal settings, so that
it can do the right thing when it asks for single keypresses or
for a password.
Commands that already use Readline, or a similar library, will always
ask for (and get) single keypresses, so that rlwrapping them doesn't
have any noticeable effect. To overcome this, one can use rlwrap with the
--always-readline (-a) option; rlwrap will then use its own line
editing and history. Unforunately, in that case, rlwrap cannot
detect whether <command> asks for a password. This can be remedied
by giving the password prompt (excluding trailing space and possibly
the first few letters) as an argument to the -a option.
EXAMPLES:
Run netcat with command-line editing:
rlwrap nc localhost 80
Run lprolog and use its saved input history and lib.pl to build a completion word list:
rlwrap -f lib.pl -f . lprolog
Run smbclient (which already uses readline), add all input and output to the completion list, complete local filenames, avoid showing (and storing) passwords:
rlwrap -cra -assword: smbclient '\\PEANUT\C'
INSTALLATION:
Usually just
./configure;
make
sudo make install
See the INSTALL file for more information.
FILTERS
Filters are perl or python plugins that enable complete (albeit
somewhat fragile) control over rlwrap's input and output, echo,
prompt, history and completion. They aren't used a lot, and remain
therefore somewhat untested. rlwrap -z listing lists the installed
filters, rlwrap -z <somefilter> displays a short help text for <somefilter>
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 ([email protected]).