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IO::Pager.3pm

NAME

IO::Pager - Select a pager, optionally pipe it output if destination is a TTY

SYNOPSIS

   #Select a pager, sets $ENV{PAGER}
   use IO::Pager;
 
 

   #Optionally pipe output
   {
     #local $STDOUT =     IO::Pager::open *STDOUT;
     local  $STDOUT = new IO::Pager       *STDOUT;
     print <<"  HEREDOC" ;
     ...
     A bunch of text later
     HEREDOC
   }
 
 

DESCRIPTION

IO::Pager is lightweight and can be used to locate an available pager and set $ENV{PAGER} (see ``NOTES'') or as a factory for creating objects defined elsewhere such as IO::Pager::Buffered and IO::Pager::Unbuffered.

IO::Pager subclasses are designed to programmatically decide whether or not to pipe a filehandle's output to a program specified in $ENV{PAGER}. Subclasses are only required to support filehandle output methods and close, namely

CLOSE

Supports close() of the filehandle.

PRINT

Supports print() to the filehandle.

PRINTF

Supports printf() to the filehandle.

WRITE

Supports syswrite() to the filehandle.

For anything else, YMMV.

new( [FILEHANDLE], [EXPR] )

Instantiate a new IO::Pager to paginate FILEHANDLE if necessary. Assign the return value to a scoped variable.

See the appropriate subclass for implementation specific details.

FILEHANDLE

Defaults to currently select()-ed FILEHANDLE.

EXPR

An expression which evaluates to the subclass of object to create.

Defaults to IO::Pager::Unbuffered.

open( [FILEHANDLE], [EXPR] )

An alias for new.

close( FILEHANDLE )

Explicitly close the filehandle, this stops any redirection of output on FILEHANDLE that may have been warranted. Normally you'd just wait for the object to pass out of scope.

This does not default to the current filehandle.

See the appropriate subclass for implementation specific details.

ENVIRONMENT

PAGER

The location of the default pager.

PATH

If PAGER does not specify an absolute path for the binary PATH may be used.

See ``NOTES'' for more information.

FILES

IO::Pager may fall back to these binaries in order if $ENV{PAGER} is not executable.

/usr/local/bin/less

/usr/bin/less

/usr/bin/more

See ``NOTES'' for more information.

NOTES

The algorythm for determining which pager is to use as follows:

1. Defer to $ENV{PAGER}

Use the value of $ENV{PAGER} if it exists unless File::Which is available and the pager in $ENV{PAGER} is determined to be unavailable.

2. Usual suspects

Try the standard, hardcoded paths in ``FILES''.

3. File::Which

If File::Which is available check for "less" and more.

4. more

Set $ENV{PAGER} to "more"

Steps 1, 3 and 4 rely upon $ENV{PATH}.

SEE ALSO

IO::Pager::Buffered, IO::Pager::Unbuffered, IO::Pager::Page

IO::Page, Tool::Less

AUTHOR

Jerrad Pierce <jpierce@cpan.org>

This module is forked from IO::Page 0.02 by Monte Mitzelfelt

LICENSE

* Thou shalt not claim ownership of unmodified materials.

* Thou shalt not claim whole ownership of modified materials.

* Thou shalt grant the indemnity of the provider of materials.

* Thou shalt use and dispense freely without other restrictions.