RLFE(1) General Commands Manual RLFE(1)NAME
rlfe - "cook" input lines for other programs using readline
SYNOPSIS
rlfe [-l filename] [-a] [-n appname] [-hv] [command [arguments ...]]
DESCRIPTION
rlfe lets you use history and line-editing in any text oriented tool. This is especially useful with third-party proprietary tools that
cannot be distributed linked against readline. It is not perfect but it works pretty well.
OPTIONS -a append to the logfile (default is to overwrite).
-l filename
log into file.
-n appname
set the readline application name.
-h print usage string.
-v print version information.
SEE ALSO readline(3)AUTHOR
Per Bothner
PROBLEMS /TODO
When running mc -c under the Linux console, mc does not recognize mouse clicks, which mc does when not running under fep.
Pasting selected text containing tabs is like hitting the tab character, which invokes readline completion. We don't want this. I don't
know if this is fixable without integrating fep into a terminal emulator.
Echo suppression is a kludge, but can only be avoided with better kernel support: We need a tty mode to disable "real" echoing, while still
letting the inferior think its tty driver to doing echoing. Stevens's book claims SCR$ and BSD4.3+ have TIOCREMOTE.
The latest readline may have some hooks we can use to avoid having to back up the prompt.
Desirable readline feature: When in cooked no-echo mode (e.g. password), echo characters are they are types with '*', but remove them when
done.
A synchronous output while we're editing an input line should be inserted in the output view.PPbefore* the input line, so that the lines
being edited (with the prompt) float at the end of the input.
A "page mode" option to emulate more/less behavior: At each page of output, pause for a user command. This required parsing the output to
keep track of line lengths. It also requires remembering the output, if we want an option to scroll back, which suggests that this should
be integrated with a terminal emulator like xterm.
RLFE(1)
Check Out this Related Man Page
Term::ReadLine(3pm) Perl Programmers Reference Guide Term::ReadLine(3pm)NAME
Term::ReadLine - Perl interface to various "readline" packages. If no real package is found, substitutes stubs instead of basic functions.
SYNOPSIS
use Term::ReadLine;
my $term = Term::ReadLine->new('Simple Perl calc');
my $prompt = "Enter your arithmetic expression: ";
my $OUT = $term->OUT || *STDOUT;
while ( defined ($_ = $term->readline($prompt)) ) {
my $res = eval($_);
warn $@ if $@;
print $OUT $res, "
" unless $@;
$term->addhistory($_) if /S/;
}
DESCRIPTION
This package is just a front end to some other packages. It's a stub to set up a common interface to the various ReadLine implementations
found on CPAN (under the "Term::ReadLine::*" namespace).
Minimal set of supported functions
All the supported functions should be called as methods, i.e., either as
$term = Term::ReadLine->new('name');
or as
$term->addhistory('row');
where $term is a return value of Term::ReadLine->new().
"ReadLine" returns the actual package that executes the commands. Among possible values are "Term::ReadLine::Gnu", "Term::ReadLine::Perl",
"Term::ReadLine::Stub".
"new" returns the handle for subsequent calls to following functions. Argument is the name of the application. Optionally can be
followed by two arguments for "IN" and "OUT" filehandles. These arguments should be globs.
"readline" gets an input line, possibly with actual "readline" support. Trailing newline is removed. Returns "undef" on "EOF".
"addhistory"
adds the line to the history of input, from where it can be used if the actual "readline" is present.
"IN", "OUT" return the filehandles for input and output or "undef" if "readline" input and output cannot be used for Perl.
"MinLine" If argument is specified, it is an advice on minimal size of line to be included into history. "undef" means do not include
anything into history. Returns the old value.
"findConsole"
returns an array with two strings that give most appropriate names for files for input and output using conventions "<$in",
">out".
Attribs returns a reference to a hash which describes internal configuration of the package. Names of keys in this hash conform to
standard conventions with the leading "rl_" stripped.
"Features" Returns a reference to a hash with keys being features present in current implementation. Several optional features are used in
the minimal interface: "appname" should be present if the first argument to "new" is recognized, and "minline" should be
present if "MinLine" method is not dummy. "autohistory" should be present if lines are put into history automatically (maybe
subject to "MinLine"), and "addhistory" if "addhistory" method is not dummy.
If "Features" method reports a feature "attribs" as present, the method "Attribs" is not dummy.
Additional supported functions
Actually "Term::ReadLine" can use some other package, that will support a richer set of commands.
All these commands are callable via method interface and have names which conform to standard conventions with the leading "rl_" stripped.
The stub package included with the perl distribution allows some additional methods:
"tkRunning" makes Tk event loop run when waiting for user input (i.e., during "readline" method).
"ornaments" makes the command line stand out by using termcap data. The argument to "ornaments" should be 0, 1, or a string of a form
"aa,bb,cc,dd". Four components of this string should be names of terminal capacities, first two will be issued to make the
prompt standout, last two to make the input line standout.
"newTTY" takes two arguments which are input filehandle and output filehandle. Switches to use these filehandles.
One can check whether the currently loaded ReadLine package supports these methods by checking for corresponding "Features".
EXPORTS
None
ENVIRONMENT
The environment variable "PERL_RL" governs which ReadLine clone is loaded. If the value is false, a dummy interface is used. If the value
is true, it should be tail of the name of the package to use, such as "Perl" or "Gnu".
As a special case, if the value of this variable is space-separated, the tail might be used to disable the ornaments by setting the tail to
be "o=0" or "ornaments=0". The head should be as described above, say
If the variable is not set, or if the head of space-separated list is empty, the best available package is loaded.
export "PERL_RL=Perl o=0" # Use Perl ReadLine without ornaments
export "PERL_RL= o=0" # Use best available ReadLine without ornaments
(Note that processing of "PERL_RL" for ornaments is in the discretion of the particular used "Term::ReadLine::*" package).
CAVEATS
It seems that using Term::ReadLine from Emacs minibuffer doesn't work quite right and one will get an error message like
Cannot open /dev/tty for read at ...
One possible workaround for this is to explicitly open /dev/tty like this
open (FH, "/dev/tty" )
or eval 'sub Term::ReadLine::findConsole { ("&STDIN", "&STDERR") }';
die $@ if $@;
close (FH);
or you can try using the 4-argument form of Term::ReadLine->new().
perl v5.12.1 2010-05-13 Term::ReadLine(3pm)