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PERLRUN(1)	 Perl Programmers Reference Guide      PERLRUN(1)

NAME
       perlrun - how to execute the Perl interpreter

SYNOPSIS
       perl [ -sTuU ]	   [ -hv ] [ -V[:configvar] ]
	    [ -cw ] [ -d[:debugger] ] [ -D[number/list] ]
	    [ -pna ] [ -Fpattern ] [ -l[octal] ] [ -0[octal] ]
	    [ -Idir ] [ -m[-]module ] [ -M[-]'module...' ]
	    [ -P ]	[ -S ]	    [ -x[dir] ]
	    [ -i[extension] ]
	    [ -e 'command' ] [ -- ] [ programfile ] [ argument ]...

DESCRIPTION
       Upon startup, Perl looks for your script in one of the
       following places:

       1.  Specified line by line via -e switches on the command
	   line.

       2.  Contained in the file specified by the first filename
	   on the command line.	 (Note that systems supporting
	   the #! notation invoke interpreters this way. See the
	   section on Location of Perl.)

       3.  Passed in implicitly via standard input.  This works
	   only if there are no filename arguments--to pass
	   arguments to a STDIN script you must explicitly
	   specify a "-" for the script name.

       With methods 2 and 3, Perl starts parsing the input file
       from the beginning, unless you've specified a -x switch,
       in which case it scans for the first line starting with #!
       and containing the word "perl", and starts there instead.
       This is useful for running a script embedded in a larger
       message.	 (In this case you would indicate the end of the
       script using the __END__ token.)

       The #! line is always examined for switches as the line is
       being parsed.  Thus, if you're on a machine that allows
       only one argument with the #! line, or worse, doesn't even
       recognize the #! line, you still can get consistent switch
       behavior regardless of how Perl was invoked, even if -x
       was used to find the beginning of the script.

       Because many operating systems silently chop off kernel
       interpretation of the #! line after 32 characters, some
       switches may be passed in on the command line, and some
       may not; you could even get a "-" without its letter, if
       you're not careful.  You probably want to make sure that
       all your switches fall either before or after that 32
       character boundary.  Most switches don't actually care if
       they're processed redundantly, but getting a - instead of
       a complete switch could cause Perl to try to execute
       standard input instead of your script.  And a partial -I


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       switch could also cause odd results.

       Some switches do care if they are processed twice, for
       instance combinations of -l and -0.  Either put all the
       switches after the 32 character boundary (if applicable),
       or replace the use of -0digits by BEGIN{ $/ = "\0digits";
       }.

       Parsing of the #! switches starts wherever "perl" is
       mentioned in the line.  The sequences "-*" and "- " are
       specifically ignored so that you could, if you were so
       inclined, say

	   #!/bin/sh -- # -*- perl -*- -p
	   eval 'exec /usr/bin/perl -wS $0 ${1+"$@"}'
	       if $running_under_some_shell;

       to let Perl see the -p switch.

       If the #! line does not contain the word "perl", the
       program named after the #! is executed instead of the Perl
       interpreter.  This is slightly bizarre, but it helps
       people on machines that don't do #!, because they can tell
       a program that their SHELL is /usr/bin/perl, and Perl will
       then dispatch the program to the correct interpreter for
       them.

       After locating your script, Perl compiles the entire
       script to an internal form.  If there are any compilation
       errors, execution of the script is not attempted.  (This
       is unlike the typical shell script, which might run part-
       way through before finding a syntax error.)

       If the script is syntactically correct, it is executed.
       If the script runs off the end without hitting an exit()
       or die() operator, an implicit exit(0) is provided to
       indicate successful completion.

       #! and quoting on non-Unix systems

       Unix's #! technique can be simulated on other systems:

       OS/2
	   Put

	       extproc perl -S -your_switches

	   as the first line in *.cmd file (-S due to a bug in
	   cmd.exe's `extproc' handling).

       MS-DOS
	   Create a batch file to run your script, and codify it
	   in ALTERNATIVE_SHEBANG (see the dosish.h file in the
	   source distribution for more information).

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       Win95/NT
	   The Win95/NT installation, when using the Activeware
	   port of Perl, will modify the Registry to associate
	   the .pl extension with the perl interpreter.	 If you
	   install another port of Perl, including the one in the
	   Win32 directory of the Perl distribution, then you'll
	   have to modify the Registry yourself.  Note that this
	   means you can no longer tell the difference between an
	   executable Perl program and a Perl library file.

       Macintosh
	   Macintosh perl scripts will have the appropriate
	   Creator and Type, so that double-clicking them will
	   invoke the perl application.

       VMS Put

	       $ perl -mysw 'f$env("procedure")' 'p1' 'p2' 'p3' 'p4' 'p5' 'p6' 'p7' 'p8' !
	       $ exit++ + ++$status != 0 and $exit = $status = undef;

	   at the top of your script, where -mysw are any command
	   line switches you want to pass to Perl.  You can now
	   invoke the script directly, by saying perl script, or
	   as a DCL procedure, by saying @script (or implicitly
	   via DCL$PATH by just using the name of the script).

	   This incantation is a bit much to remember, but Perl
	   will display it for you if you say perl
	   "-V:startperl".

       Command-interpreters on non-Unix systems have rather
       different ideas on quoting than Unix shells.  You'll need
       to learn the special characters in your command-
       interpreter (*, \ and " are common) and how to protect
       whitespace and these characters to run one-liners (see -e
       below).

       On some systems, you may have to change single-quotes to
       double ones, which you must NOT do on Unix or Plan9
       systems.	 You might also have to change a single % to a
       %%.

       For example:

	   # Unix
	   perl -e 'print "Hello world\n"'

	   # MS-DOS, etc.
	   perl -e "print \"Hello world\n\""

	   # Macintosh
	   print "Hello world\n"
	    (then Run "Myscript" or Shift-Command-R)

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	   # VMS
	   perl -e "print ""Hello world\n"""

       The problem is that none of this is reliable: it depends
       on the command and it is entirely possible neither works.
       If 4DOS was the command shell, this would probably work
       better:

	   perl -e "print <Ctrl-x>"Hello world\n<Ctrl-x>""

       CMD.EXE in Windows NT slipped a lot of standard Unix
       functionality in when nobody was looking, but just try to
       find documentation for its quoting rules.

       Under the Macintosh, it depends which environment you are
       using.  The MacPerl shell, or MPW, is much like Unix
       shells in its support for several quoting variants, except
       that it makes free use of the Macintosh's non-ASCII
       characters as control characters.

       There is no general solution to all of this.  It's just a
       mess.

       Location of Perl

       It may seem obvious to say, but Perl is useful only when
       users can easily find it. When possible, it's good for
       both /usr/bin/perl and /usr/local/bin/perl to be symlinks
       to the actual binary. If that can't be done, system
       administrators are strongly encouraged to put (symlinks
       to) perl and its accompanying utilities, such as perldoc,
       into a directory typically found along a user's PATH, or
       in another obvious and convenient place.

       In this documentation, #!/usr/bin/perl on the first line
       of the script will stand in for whatever method works on
       your system.

       Switches

       A single-character switch may be combined with the
       following switch, if any.

	   #!/usr/bin/perl -spi.bak    # same as -s -p -i.bak

       Switches include:

       -0[digits]
	    specifies the input record separator ($/) as an octal
	    number.  If there are no digits, the null character
	    is the separator.  Other switches may precede or
	    follow the digits.	For example, if you have a
	    version of find which can print filenames terminated
	    by the null character, you can say this:

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		find . -name '*.bak' -print0 | perl -n0e unlink

	    The special value 00 will cause Perl to slurp files
	    in paragraph mode.	The value 0777 will cause Perl to
	    slurp files whole because there is no legal character
	    with that value.

       -a   turns on autosplit mode when used with a -n or -p.
	    An implicit split command to the @F array is done as
	    the first thing inside the implicit while loop
	    produced by the -n or -p.

		perl -ane 'print pop(@F), "\n";'

	    is equivalent to

		while (<>) {
		    @F = split(' ');
		    print pop(@F), "\n";
		}

	    An alternate delimiter may be specified using -F.

       -c   causes Perl to check the syntax of the script and
	    then exit without executing it.  Actually, it will
	    execute BEGIN, END, and use blocks, because these are
	    considered as occurring outside the execution of your
	    program.

       -d   runs the script under the Perl debugger.  See the
	    perldebug manpage.

       -d:foo
	    runs the script under the control of a debugging or
	    tracing module installed as Devel::foo. E.g.,
	    -d:DProf executes the script using the Devel::DProf
	    profiler.  See the perldebug manpage.

       -Dletters

       -Dnumber
	    sets debugging flags.  To watch how it executes your
	    script, use -Dtls.	(This works only if debugging is
	    compiled into your Perl.)  Another nice value is -Dx,
	    which lists your compiled syntax tree.  And -Dr
	    displays compiled regular expressions. As an
	    alternative, specify a number instead of list of
	    letters (e.g., -D14 is equivalent to -Dtls):

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		    1  p  Tokenizing and parsing
		    2  s  Stack snapshots
		    4  l  Context (loop) stack processing
		    8  t  Trace execution
		   16  o  Method and overloading resolution
		   32  c  String/numeric conversions
		   64  P  Print preprocessor command for -P
		  128  m  Memory allocation
		  256  f  Format processing
		  512  r  Regular expression parsing and execution
		 1024  x  Syntax tree dump
		 2048  u  Tainting checks
		 4096  L  Memory leaks (needs C<-DLEAKTEST> when compiling Perl)
		 8192  H  Hash dump -- usurps values()
		16384  X  Scratchpad allocation
		32768  D  Cleaning up
		65536  S  Thread synchronization

	    All these flags require -DDEBUGGING when you compile
	    the Perl executable.  This flag is automatically set
	    if you include -g option when Configure asks you
	    about optimizer/debugger flags.

       -e commandline
	    may be used to enter one line of script.  If -e is
	    given, Perl will not look for a script filename in
	    the argument list.	Multiple -e commands may be given
	    to build up a multi-line script.  Make sure to use
	    semicolons where you would in a normal program.

       -Fpattern
	    specifies the pattern to split on if -a is also in
	    effect.  The pattern may be surrounded by //, "", or
	    '', otherwise it will be put in single quotes.

       -h   prints a summary of the options.

       -i[extension]
	    specifies that files processed by the <> construct
	    are to be edited in-place.	It does this by renaming
	    the input file, opening the output file by the
	    original name, and selecting that output file as the
	    default for print() statements.  The extension, if
	    supplied, is used to modify the name of the old file
	    to make a backup copy, following these rules:

	    If no extension is supplied, no backup is made and
	    the current file is overwritten.

	    If the extension doesn't contain a * then it is
	    appended to the end of the current filename as a
	    suffix.

	    If the extension does contain one or more *

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	    characters, then each * is replaced with the current
	    filename.  In perl terms you could think of this as:

		($backup = $extension) =~ s/\*/$file_name/g;

	    This allows you to add a prefix to the backup file,
	    instead of (or in addition to) a suffix:

		$ perl -pi'bak_*' -e 's/bar/baz/' fileA	    # backup to 'bak_fileA'

	    Or even to place backup copies of the original files
	    into another directory (provided the directory
	    already exists):

		$ perl -pi'old/*.bak' -e 's/bar/baz/' fileA # backup to 'old/fileA.bak'

	    These sets of one-liners are equivalent:

		$ perl -pi -e 's/bar/baz/' fileA	    # overwrite current file
		$ perl -pi'*' -e 's/bar/baz/' fileA	    # overwrite current file

		$ perl -pi'.bak' -e 's/bar/baz/' fileA	    # backup to 'fileA.bak'
		$ perl -pi'*.bak' -e 's/bar/baz/' fileA	    # backup to 'fileA.bak'

	    From the shell, saying

		$ perl -p -i.bak -e "s/foo/bar/; ... "

	    is the same as using the script:

		#!/usr/bin/perl -pi.bak
		s/foo/bar/;

	    which is equivalent to

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		#!/usr/bin/perl
		$extension = '.bak';
		while (<>) {
		    if ($ARGV ne $oldargv) {
			if ($extension !~ /\*/) {
			    $backup = $ARGV . $extension;
			}
			else {
			    ($backup = $extension) =~ s/\*/$ARGV/g;
			}
			rename($ARGV, $backup);
			open(ARGVOUT, ">$ARGV");
			select(ARGVOUT);
			$oldargv = $ARGV;
		    }
		    s/foo/bar/;
		}
		continue {
		    print;  # this prints to original filename
		}
		select(STDOUT);

	    except that the -i form doesn't need to compare $ARGV
	    to $oldargv to know when the filename has changed.
	    It does, however, use ARGVOUT for the selected
	    filehandle.	 Note that STDOUT is restored as the
	    default output filehandle after the loop.

	    As shown above, Perl creates the backup file whether
	    or not any output is actually changed.  So this is
	    just a fancy way to copy files:

		$ perl -p -i'/some/file/path/*' -e 1 file1 file2 file3...
	      or
		$ perl -p -i'.bak' -e 1 file1 file2 file3...

	    You can use eof without parentheses to locate the end
	    of each input file, in case you want to append to
	    each file, or reset line numbering (see example in
	    the eof entry in the perlfunc manpage).

	    If, for a given file, Perl is unable to create the
	    backup file as specified in the extension then it
	    will skip that file and continue on with the next one
	    (if it exists).

	    For a discussion of issues surrounding file
	    permissions and -i, see the section on Why does Perl
	    let me delete read-only files?  Why does -i clobber
	    protected files?  Isn't this a bug in Perl? in the
	    perlfaq5 manpage.

	    You cannot use -i to create directories or to strip
	    extensions from files.

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	    Perl does not expand ~, so don't do that.

	    Finally, note that the -i switch does not impede
	    execution when no files are given on the command
	    line.  In this case, no backup is made (the original
	    file cannot, of course, be determined) and processing
	    proceeds from STDIN to STDOUT as might be expected.

       -Idirectory
	    Directories specified by -I are prepended to the
	    search path for modules (@INC), and also tells the C
	    preprocessor where to search for include files.  The
	    C preprocessor is invoked with -P; by default it
	    searches /usr/include and /usr/lib/perl.

       -l[octnum]
	    enables automatic line-ending processing.  It has two
	    effects:  first, it automatically chomps "$/" (the
	    input record separator) when used with -n or -p, and
	    second, it assigns "$\" (the output record separator)
	    to have the value of octnum so that any print
	    statements will have that separator added back on.
	    If octnum is omitted, sets "$\" to the current value
	    of "$/".  For instance, to trim lines to 80 columns:

		perl -lpe 'substr($_, 80) = ""'

	    Note that the assignment $\ = $/ is done when the
	    switch is processed, so the input record separator
	    can be different than the output record separator if
	    the -l switch is followed by a -0 switch:

		gnufind / -print0 | perl -ln0e 'print "found $_" if -p'

	    This sets $\ to newline and then sets $/ to the null
	    character.

       -m[-]module

       -M[-]module

       -M[-]'module ...'

       -[mM][-]module=arg[,arg]...
	    -mmodule executes use module (); before executing
	    your script.

	    -Mmodule executes use module ; before executing your
	    script.  You can use quotes to add extra code after
	    the module name, e.g., -M'module qw(foo bar)'.

	    If the first character after the -M or -m is a dash
	    (-) then the 'use' is replaced with 'no'.

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	    A little builtin syntactic sugar means you can also
	    say -mmodule=foo,bar or -Mmodule=foo,bar as a
	    shortcut for -M'module qw(foo bar)'.  This avoids the
	    need to use quotes when importing symbols.	The
	    actual code generated by -Mmodule=foo,bar is use
	    module split(/,/,q{foo,bar}).  Note that the = form
	    removes the distinction between -m and -M.

       -n   causes Perl to assume the following loop around your
	    script, which makes it iterate over filename
	    arguments somewhat like sed -n or awk:

		while (<>) {
		    ...		    # your script goes here
		}

	    Note that the lines are not printed by default.  See
	    -p to have lines printed.  If a file named by an
	    argument cannot be opened for some reason, Perl warns
	    you about it, and moves on to the next file.

	    Here is an efficient way to delete all files older
	    than a week:

		find . -mtime +7 -print | perl -nle 'unlink;'

	    This is faster than using the -exec switch of find
	    because you don't have to start a process on every
	    filename found.

	    BEGIN and END blocks may be used to capture control
	    before or after the implicit loop, just as in awk.

       -p   causes Perl to assume the following loop around your
	    script, which makes it iterate over filename
	    arguments somewhat like sed:

		while (<>) {
		    ...		    # your script goes here
		} continue {
		    print or die "-p destination: $!\n";
		}

	    If a file named by an argument cannot be opened for
	    some reason, Perl warns you about it, and moves on to
	    the next file.  Note that the lines are printed
	    automatically.  An error occurring during printing is
	    treated as fatal.  To suppress printing use the -n
	    switch.  A -p overrides a -n switch.

	    BEGIN and END blocks may be used to capture control
	    before or after the implicit loop, just as in awk.

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       -P   causes your script to be run through the C
	    preprocessor before compilation by Perl.  (Because
	    both comments and cpp directives begin with the #
	    character, you should avoid starting comments with
	    any words recognized by the C preprocessor such as
	    "if", "else", or "define".)

       -s   enables some rudimentary switch parsing for switches
	    on the command line after the script name but before
	    any filename arguments (or before a --).  Any switch
	    found there is removed from @ARGV and sets the
	    corresponding variable in the Perl script.	The
	    following script prints "true" if and only if the
	    script is invoked with a -xyz switch.

		#!/usr/bin/perl -s
		if ($xyz) { print "true\n"; }

       -S   makes Perl use the PATH environment variable to
	    search for the script (unless the name of the script
	    contains directory separators).  On some platforms,
	    this also makes Perl append suffixes to the filename
	    while searching for it.  For example, on Win32
	    platforms, the ".bat" and ".cmd" suffixes are
	    appended if a lookup for the original name fails, and
	    if the name does not already end in one of those
	    suffixes.  If your Perl was compiled with DEBUGGING
	    turned on, using the -Dp switch to Perl shows how the
	    search progresses.

	    If the filename supplied contains directory
	    separators (i.e. it is an absolute or relative
	    pathname), and if the file is not found, platforms
	    that append file extensions will do so and try to
	    look for the file with those extensions added, one by
	    one.

	    On DOS-like platforms, if the script does not contain
	    directory separators, it will first be searched for
	    in the current directory before being searched for on
	    the PATH.  On Unix platforms, the script will be
	    searched for strictly on the PATH.

	    Typically this is used to emulate #! startup on
	    platforms that don't support #!.  This example works
	    on many platforms that have a shell compatible with
	    Bourne shell:

		#!/usr/bin/perl
		eval 'exec /usr/bin/perl -wS $0 ${1+"$@"}'
			if $running_under_some_shell;

	    The system ignores the first line and feeds the

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	    script to /bin/sh, which proceeds to try to execute
	    the Perl script as a shell script.	The shell
	    executes the second line as a normal shell command,
	    and thus starts up the Perl interpreter.  On some
	    systems $0 doesn't always contain the full pathname,
	    so the -S tells Perl to search for the script if
	    necessary.	After Perl locates the script, it parses
	    the lines and ignores them because the variable
	    $running_under_some_shell is never true. If the
	    script will be interpreted by csh, you will need to
	    replace ${1+"$@"} with $*, even though that doesn't
	    understand embedded spaces (and such) in the argument
	    list.  To start up sh rather than csh, some systems
	    may have to replace the #! line with a line
	    containing just a colon, which will be politely
	    ignored by Perl.  Other systems can't control that,
	    and need a totally devious construct that will work
	    under any of csh, sh, or Perl, such as the following:

		    eval '(exit $?0)' && eval 'exec /usr/bin/perl -wS $0 ${1+"$@"}'
		    & eval 'exec /usr/bin/perl -wS $0 $argv:q'
			    if $running_under_some_shell;

       -T   forces "taint" checks to be turned on so you can test
	    them.  Ordinarily these checks are done only when
	    running setuid or setgid.  It's a good idea to turn
	    them on explicitly for programs run on another's
	    behalf, such as CGI programs.  See the perlsec
	    manpage.  Note that (for security reasons) this
	    option must be seen by Perl quite early; usually this
	    means it must appear early on the command line or in
	    the #! line (for systems which support that).

       -u   causes Perl to dump core after compiling your script.
	    You can then in theory take this core dump and turn
	    it into an executable file by using the undump
	    program (not supplied).  This speeds startup at the
	    expense of some disk space (which you can minimize by
	    stripping the executable).	(Still, a "hello world"
	    executable comes out to about 200K on my machine.)
	    If you want to execute a portion of your script
	    before dumping, use the dump() operator instead.
	    Note: availability of undump is platform specific and
	    may not be available for a specific port of Perl.  It
	    has been superseded by the new perl-to-C compiler,
	    which is more portable, even though it's still only
	    considered beta.

       -U   allows Perl to do unsafe operations.  Currently the
	    only "unsafe" operations are the unlinking of
	    directories while running as superuser, and running
	    setuid programs with fatal taint checks turned into
	    warnings. Note that the -w switch (or the $^W

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	    variable) must be used along with this option to
	    actually generate the taint-check warnings.

       -v   prints the version and patchlevel of your Perl
	    executable.

       -V   prints summary of the major perl configuration values
	    and the current value of @INC.

       -V:name
	    Prints to STDOUT the value of the named configuration
	    variable.

       -w   prints warnings about variable names that are
	    mentioned only once, and scalar variables that are
	    used before being set.  Also warns about redefined
	    subroutines, and references to undefined filehandles
	    or filehandles opened read-only that you are
	    attempting to write on.  Also warns you if you use
	    values as a number that doesn't look like numbers,
	    using an array as though it were a scalar, if your
	    subroutines recurse more than 100 deep, and
	    innumerable other things.

	    You can disable specific warnings using __WARN__
	    hooks, as described in the perlvar manpage and the
	    warn entry in the perlfunc manpage. See also the
	    perldiag manpage and the perltrap manpage.

       -x directory
	    tells Perl that the script is embedded in a message.
	    Leading garbage will be discarded until the first
	    line that starts with #! and contains the string
	    "perl".  Any meaningful switches on that line will be
	    applied.  If a directory name is specified, Perl will
	    switch to that directory before running the script.
	    The -x switch controls only the disposal of leading
	    garbage.  The script must be terminated with __END__
	    if there is trailing garbage to be ignored (the
	    script can process any or all of the trailing garbage
	    via the DATA filehandle if desired).

ENVIRONMENT
       HOME	   Used if chdir has no argument.

       LOGDIR	   Used if chdir has no argument and HOME is not
		   set.

       PATH	   Used in executing subprocesses, and in finding
		   the script if -S is used.

       PERL5LIB	   A colon-separated list of directories in which
		   to look for Perl library files before looking
		   in the standard library and the current

16/Sep/1999	       perl 5.005, patch 03		       13

PERLRUN(1)	 Perl Programmers Reference Guide      PERLRUN(1)

		   directory.  If PERL5LIB is not defined,
		   PERLLIB is used.  When running taint checks
		   (because the script was running setuid or
		   setgid, or the -T switch was used), neither
		   variable is used.  The script should instead
		   say

		       use lib "/my/directory";

       PERL5OPT	   Command-line options (switches).  Switches in
		   this variable are taken as if they were on
		   every Perl command line.  Only the -[DIMUdmw]
		   switches are allowed.  When running taint
		   checks (because the script was running setuid
		   or setgid, or the -T switch was used), this
		   variable is ignored.	 If PERL5OPT begins with
		   -T, tainting will be enabled, and any
		   subsequent options ignored.

       PERLLIB	   A colon-separated list of directories in which
		   to look for Perl library files before looking
		   in the standard library and the current
		   directory.  If PERL5LIB is defined, PERLLIB is
		   not used.

       PERL5DB	   The command used to load the debugger code.
		   The default is:

			   BEGIN { require 'perl5db.pl' }

       PERL5SHELL (specific to WIN32 port)
		   May be set to an alternative shell that perl
		   must use internally for executing "backtick"
		   commands or system().  Default is cmd.exe /x/c
		   on WindowsNT and command.com /c on Windows95.
		   The value is considered to be space delimited.
		   Precede any character that needs to be
		   protected (like a space or backslash) with a
		   backslash.

		   Note that Perl doesn't use COMSPEC for this
		   purpose because COMSPEC has a high degree of
		   variability among users, leading to
		   portability concerns.  Besides, perl can use a
		   shell that may not be fit for interactive use,
		   and setting COMSPEC to such a shell may
		   interfere with the proper functioning of other
		   programs (which usually look in COMSPEC to
		   find a shell fit for interactive use).

       PERL_DEBUG_MSTATS
		   Relevant only if perl is compiled with the

16/Sep/1999	       perl 5.005, patch 03		       14

PERLRUN(1)	 Perl Programmers Reference Guide      PERLRUN(1)

		   malloc included with the perl distribution
		   (that is, if perl -V:d_mymalloc is 'define').
		   If set, this causes memory statistics to be
		   dumped after execution.  If set to an integer
		   greater than one, also causes memory
		   statistics to be dumped after compilation.

       PERL_DESTRUCT_LEVEL
		   Relevant only if your perl executable was
		   built with -DDEBUGGING, this controls the
		   behavior of global destruction of objects and
		   other references.

       Perl also has environment variables that control how Perl
       handles data specific to particular natural languages.
       See the perllocale manpage.

       Apart from these, Perl uses no other environment
       variables, except to make them available to the script
       being executed, and to child processes.	However, scripts
       running setuid would do well to execute the following
       lines before doing anything else, just to keep people
       honest:

	   $ENV{PATH} = '/bin:/usr/bin';    # or whatever you need
	   $ENV{SHELL} = '/bin/sh' if exists $ENV{SHELL};
	   delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};

16/Sep/1999	       perl 5.005, patch 03		       15

PERLRUN(1)	 Perl Programmers Reference Guide      PERLRUN(1)

16/Sep/1999	       perl 5.005, patch 03		       16

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