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perlrun ()
  • >> perlrun (1) ( Solaris man: Команды и прикладные программы пользовательского уровня )
  • perlrun (1) ( Разные man: Команды и прикладные программы пользовательского уровня )
  • 
    
    

    NAME

         perlrun - how to execute the Perl interpreter
    
    
    

    SYNOPSIS

         perl [ -CsTuUWX ]      [ -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

         The normal way to run a Perl program is by making it
         directly executable, or else by passing the name of the
         source file as an argument on the command line.  (An
         interactive Perl environment is also possible--see the
         perldebug manpage for details on how to do that.)  Upon
         startup, Perl looks for your program 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 Location
             of Perl entry elsewhere in this document.)
    
         3.  Passed in implicitly via standard input.  This works
             only if there are no filename arguments--to pass
             arguments to a STDIN-read program you must explicitly
             specify a "-" for the program 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 program embedded in a larger
         message.  (In this case you would indicate the end of the
         program 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 program.
    
         Because historically some operating systems silently chopped
         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 program.  And a partial -I
         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 perl -wS $0 ${1+"$@"}'
                 if $running_under_some_shell;
    
         to let Perl see the -p switch.
    
         A similar trick involves the env program, if you have it.
    
             #!/usr/bin/env perl
    
         The examples above use a relative path to the perl
         interpreter, getting whatever version is first in the user's
         path.  If you want a specific version of Perl, say,
         perl5.005_57, you should place that directly in the #!
         line's path.
    
         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 program, Perl compiles the entire
         program to an internal form.  If there are any compilation
         errors, execution of the program is not attempted.  (This is
         unlike the typical shell script, which might run part-way
         through before finding a syntax error.)
    
         If the program is syntactically correct, it is executed.  If
         the program 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 program, and codify it
             in `ALTERNATIVE_SHEBANG' (see the dosish.h file in the
             source distribution for more information).
    
         Win95/NT
             The Win95/NT installation, when using the ActiveState
             installer for Perl, will modify the Registry to
             associate the .pl extension with the perl interpreter.
             If you install Perl by other means (including building
             from the sources), you may 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
             A Macintosh perl program 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 program, where -mysw are any command
             line switches you want to pass to Perl.  You can now
             invoke the program directly, by saying `perl program',
             or as a DCL procedure, by saying `@program' (or
             implicitly via DCL$PATH by just using the name of the
             program).
    
             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)
    
             # 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 were 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 into a directory typically found
         along a user's PATH, or in some other obvious and convenient
         place.
    
         In this documentation, `#!/usr/bin/perl' on the first line
         of the program will stand in for whatever method works on
         your system.  You are advised to use a specific path if you
         care about a specific version.
    
             #!/usr/local/bin/perl5.00554
    
         or if you just want to be running at least version, place a
         statement like this at the top of your program:
    
             use 5.005_54;
    
    
         Command Switches
    
         As with all standard commands, a single-character switch may
         be clustered with the following switch, if any.
    
             #!/usr/bin/perl -spi.orig   # same as -s -p -i.orig
    
         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:
    
                  find . -name '*.orig' -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   enables Perl to use the native wide character APIs on
              the target system.  The magic variable
              `${^WIDE_SYSTEM_CALLS}' reflects the state of this
              switch.  See the section on "${^WIDE_SYSTEM_CALLS}" in
              the perlvar manpage.
    
              This feature is currently only implemented on the Win32
              platform.
    
         -c   causes Perl to check the syntax of the program and then
              exit without executing it.  Actually, it will execute
              `BEGIN', `CHECK', and `use' blocks, because these are
              considered as occurring outside the execution of your
              program.  `INIT' and `END' blocks, however, will be
              skipped.
    
         -d   runs the program under the Perl debugger.  See the
              perldebug manpage.
    
         -d:foo
              runs the program under the control of a debugging,
              profiling, or tracing module installed as Devel::foo.
              E.g., -d:DProf executes the program using the
              Devel::DProf profiler.  See the perldebug manpage.
    
         -Dletters
    
         -Dnumber
              sets debugging flags.  To watch how it executes your
              program, 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):
    
    
    
                      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 -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.  See the INSTALL file in the Perl
              source distribution for how to do this.  This flag is
              automatically set if you include -g option when
              `Configure' asks you about optimizer/debugger flags.
    
              If you're just trying to get a print out of each line
              of Perl code as it executes, the way that `sh -x'
              provides for shell scripts, you can't use Perl's -D
              switch.  Instead do this
    
                # Bourne shell syntax
                $ PERLDB_OPTS="NonStop=1 AutoTrace=1 frame=2" perl -dS program
    
                # csh syntax
                % (setenv PERLDB_OPTS "NonStop=1 AutoTrace=1 frame=2"; perl -dS program)
    
              See the perldebug manpage for details and variations.
    
         -e commandline
              may be used to enter one line of program.  If -e is
              given, Perl will not look for a 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 `*'
              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 'orig_*' -e 's/bar/baz/' fileA   # backup to 'orig_fileA'
    
              Or even to place backup copies of the original files
              into another directory (provided the directory already
              exists):
    
                  $ perl -pi 'old/*.orig' -e 's/bar/baz/' fileA # backup to 'old/fileA.orig'
    
              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 '.orig' -e 's/bar/baz/' fileA    # backup to 'fileA.orig'
                  $ perl -pi '*.orig' -e 's/bar/baz/' fileA   # backup to 'fileA.orig'
    
              From the shell, saying
    
                  $ perl -p -i.orig -e "s/foo/bar/; ... "
    
              is the same as using the program:
    
                  #!/usr/bin/perl -pi.orig
                  s/foo/bar/;
    
              which is equivalent to
    
    
    
                  #!/usr/bin/perl
                  $extension = '.orig';
                  LINE: while (<>) {
                      if ($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 '.orig' -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 Why does Perl let me delete read-only
              files? Why does -i clobber protected files? Isn't this
              a bug in Perl? entry in the perlfaq5 manpage.
    
              You cannot use -i to create directories or to strip
              extensions from files.
    
              Perl does not expand `~' in filenames, which is good,
              since some folks use it for their backup files:
    
                  $ perl -pi~ -e 's/foo/bar/' file1 file2 file3...
    
              Finally, 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
              separate effects.  First, it automatically chomps `$/'
              (the input record separator) when used with -n or -p.
              Second, it assigns `$\' (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 program.
    
              -Mmodule executes `use' module `;' before executing
              your program.  You can use quotes to add extra code
              after the module name, e.g., `'-Mmodule qw(foo bar)''.
    
              If the first character after the -M or -m is a dash
              (`-') then the 'use' is replaced with 'no'.
    
              A little builtin syntactic sugar means you can also say
              -mmodule=foo,bar or -Mmodule=foo,bar as a shortcut for
              `'-Mmodule 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
              program, which makes it iterate over filename arguments
              somewhat like sed -n or awk:
    
                LINE:
                  while (<>) {
                      ...             # your program 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.  It does suffer from the bug of
              mishandling newlines in pathnames, which you can fix if
              you
    
              `BEGIN' and `END' blocks may be used to capture control
              before or after the implicit program loop, just as in
              awk.
    
         -p   causes Perl to assume the following loop around your
              program, which makes it iterate over filename arguments
              somewhat like sed:
    
    
    
                LINE:
                  while (<>) {
                      ...             # your program 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.
    
         -P   causes your program 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 rudimentary switch parsing for switches on the
              command line after the program 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 program.  The following program
              prints "1" if the program is invoked with a -xyz
              switch, and "abc" if it is invoked with -xyz=abc.
    
                  #!/usr/bin/perl -s
                  if ($xyz) { print "$xyz\n" }
    
    
         -S   makes Perl use the PATH environment variable to search
              for the program (unless the name of the program
              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.
    
              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 program
              to /bin/sh, which proceeds to try to execute the Perl
              program 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 program if necessary.  After Perl
              locates the program, it parses the lines and ignores
              them because the variable $running_under_some_shell is
              never true.  If the program will be interpreted by csh,
              you will need to replace `${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 perl -wS $0 ${1+"$@"}'
                      & eval 'exec /usr/bin/perl -wS $0 $argv:q'
                              if $running_under_some_shell;
    
              If the filename supplied contains directory separators
              (i.e., is an absolute or relative pathname), and if
              that 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 program 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 program will be searched
              for strictly on the PATH.
    
         -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 that run on behalf of
              someone else whom you might not necessarily trust, such
              as CGI programs or any internet servers you might write
              in Perl.  See the perlsec manpage for details.  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 construct.
    
         -u   This obsolete switch causes Perl to dump core after
              compiling your program.  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
              program 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.
    
              This switch has been superseded in favor of the new
              Perl code generator backends to the compiler.  See the
              B manpage and the B::Bytecode manpage for details.
    
         -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'
              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 values of @INC.
    
         -V:name
              Prints to STDOUT the value of the named configuration
              variable.  For example,
    
                  $ perl -V:man.dir
    
              will provide strong clues about what your MANPATH
              variable should be set to in order to access the Perl
              documentation.
    
         -w   prints warnings about dubious constructs, such as
              variable names that are mentioned only once and scalar
              variables that are used before being set, redefined
              subroutines, references to undefined filehandles or
              filehandles opened read-only that you are attempting to
              write on, values used 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.
    
              This switch really just enables the internal `^$W'
              variable.  You can disable or promote into fatal errors
              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.  A new, fine-grained warning
              facility is also available if you want to manipulate
              entire classes of warnings; see the warnings manpage or
              the perllexwarn manpage.
    
         -W   Enables all warnings regardless of `no warnings' or
              `$^W'.  See the perllexwarn manpage.
    
         -X   Disables all warnings regardless of `use warnings' or
              `$^W'.  See the perllexwarn manpage.
    
         -x directory
              tells Perl that the program is embedded in a larger
              chunk of unrelated ASCII text, such as in a mail
              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 program.
              The -x switch controls only the disposal of leading
              garbage.  The program must be terminated with `__END__'
              if there is trailing garbage to be ignored (the program
              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 program 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 directory.
                     Any architecture-specific directories under the
                     specified locations are automatically included
                     if they exist.  If PERL5LIB is not defined,
                     PERLLIB is used.
    
                     When running taint checks (either because the
                     program was running setuid or setgid, or the -T
                     switch was used), neither variable is used.  The
                     program 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 program 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 the 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-separated.
                     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
                     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 program being executed,
         and to child processes.  However, programs 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)};
    
    
    
    


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