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1=head1 NAME
2
3perlrun - how to execute the Perl interpreter
4
5=head1 SYNOPSIS
6
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7B<perl> S<[ B<-sTuU> ]>
8 S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
9 S<[ B<-cw> ] [ B<-d>[:I<debugger>] ] [ B<-D>[I<number/list>] ]>
10 S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal>] ]>
11 S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ]>
12 S<[ B<-P> ]>
13 S<[ B<-S> ]>
14 S<[ B<-x>[I<dir>] ]>
15 S<[ B<-i>[I<extension>] ]>
16 S<[ B<-e> I<'command'> ] [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
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17
18=head1 DESCRIPTION
19
20Upon startup, Perl looks for your script in one of the following
21places:
22
23=over 4
24
25=item 1.
26
27Specified line by line via B<-e> switches on the command line.
28
29=item 2.
30
31Contained in the file specified by the first filename on the command line.
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32(Note that systems supporting the #! notation invoke interpreters this
33way. See L<Location of Perl>.)
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34
35=item 3.
36
5f05dabc 37Passed in implicitly via standard input. This works only if there are
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38no filename arguments--to pass arguments to a STDIN script you
39must explicitly specify a "-" for the script name.
40
41=back
42
43With methods 2 and 3, Perl starts parsing the input file from the
44beginning, unless you've specified a B<-x> switch, in which case it
45scans for the first line starting with #! and containing the word
46"perl", and starts there instead. This is useful for running a script
47embedded in a larger message. (In this case you would indicate the end
54310121 48of the script using the C<__END__> token.)
a0d0e21e 49
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50The #! line is always examined for switches as the line is being
51parsed. Thus, if you're on a machine that allows only one argument
52with the #! line, or worse, doesn't even recognize the #! line, you
53still can get consistent switch behavior regardless of how Perl was
54invoked, even if B<-x> was used to find the beginning of the script.
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55
56Because many operating systems silently chop off kernel interpretation of
57the #! line after 32 characters, some switches may be passed in on the
58command line, and some may not; you could even get a "-" without its
59letter, if you're not careful. You probably want to make sure that all
60your switches fall either before or after that 32 character boundary.
61Most switches don't actually care if they're processed redundantly, but
62getting a - instead of a complete switch could cause Perl to try to
63execute standard input instead of your script. And a partial B<-I> switch
64could also cause odd results.
65
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66Some switches do care if they are processed twice, for instance combinations
67of B<-l> and B<-0>. Either put all the switches after the 32 character
68boundary (if applicable), or replace the use of B<-0>I<digits> by
69C<BEGIN{ $/ = "\0digits"; }>.
70
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71Parsing of the #! switches starts wherever "perl" is mentioned in the line.
72The sequences "-*" and "- " are specifically ignored so that you could,
73if you were so inclined, say
74
75 #!/bin/sh -- # -*- perl -*- -p
a3cb178b 76 eval 'exec /usr/bin/perl -wS $0 ${1+"$@"}'
5f05dabc 77 if $running_under_some_shell;
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78
79to let Perl see the B<-p> switch.
80
81If the #! line does not contain the word "perl", the program named after
82the #! is executed instead of the Perl interpreter. This is slightly
83bizarre, but it helps people on machines that don't do #!, because they
84can tell a program that their SHELL is /usr/bin/perl, and Perl will then
85dispatch the program to the correct interpreter for them.
86
87After locating your script, Perl compiles the entire script to an
88internal form. If there are any compilation errors, execution of the
89script is not attempted. (This is unlike the typical shell script,
54310121 90which might run part-way through before finding a syntax error.)
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91
92If the script is syntactically correct, it is executed. If the script
93runs off the end without hitting an exit() or die() operator, an implicit
94C<exit(0)> is provided to indicate successful completion.
95
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96=head2 #! and quoting on non-Unix systems
97
98Unix's #! technique can be simulated on other systems:
99
100=over 4
101
102=item OS/2
103
104Put
105
106 extproc perl -S -your_switches
107
108as the first line in C<*.cmd> file (C<-S> due to a bug in cmd.exe's
109`extproc' handling).
110
54310121 111=item MS-DOS
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112
113Create a batch file to run your script, and codify it in
114C<ALTERNATIVE_SHEBANG> (see the F<dosish.h> file in the source
115distribution for more information).
116
117=item Win95/NT
118
119The Win95/NT installation, when using the Activeware port of Perl,
c8db1d39 120will modify the Registry to associate the F<.pl> extension with the perl
68dc0745 121interpreter. If you install another port of Perl, including the one
4a6725af 122in the Win32 directory of the Perl distribution, then you'll have to
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123modify the Registry yourself. Note that this means you can no
124longer tell the difference between an executable Perl program
125and a Perl library file.
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126
127=item Macintosh
128
10a676f8 129Macintosh perl scripts will have the appropriate Creator and
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130Type, so that double-clicking them will invoke the perl application.
131
132=back
133
134Command-interpreters on non-Unix systems have rather different ideas
135on quoting than Unix shells. You'll need to learn the special
136characters in your command-interpreter (C<*>, C<\> and C<"> are
137common) and how to protect whitespace and these characters to run
138one-liners (see C<-e> below).
139
140On some systems, you may have to change single-quotes to double ones,
141which you must I<NOT> do on Unix or Plan9 systems. You might also
142have to change a single % to a %%.
143
144For example:
145
146 # Unix
147 perl -e 'print "Hello world\n"'
148
54310121 149 # MS-DOS, etc.
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150 perl -e "print \"Hello world\n\""
151
54310121 152 # Macintosh
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153 print "Hello world\n"
154 (then Run "Myscript" or Shift-Command-R)
155
156 # VMS
157 perl -e "print ""Hello world\n"""
158
159The problem is that none of this is reliable: it depends on the command
54310121 160and it is entirely possible neither works. If 4DOS was the command shell, this would
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161probably work better:
162
163 perl -e "print <Ctrl-x>"Hello world\n<Ctrl-x>""
164
165CMD.EXE in Windows NT slipped a lot of standard Unix functionality in
166when nobody was looking, but just try to find documentation for its
167quoting rules.
168
54310121 169Under the Macintosh, it depends which environment you are using. The MacPerl
68dc0745 170shell, or MPW, is much like Unix shells in its support for several
54310121 171quoting variants, except that it makes free use of the Macintosh's non-ASCII
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172characters as control characters.
173
174There is no general solution to all of this. It's just a mess.
175
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176=head2 Location of Perl
177
178It may seem obvious to say, but Perl is useful only when users can
179easily find it. When possible, it's good for both B</usr/bin/perl> and
180B</usr/local/bin/perl> to be symlinks to the actual binary. If that
181can't be done, system administrators are strongly encouraged to put
182(symlinks to) perl and its accompanying utilities, such as perldoc, into
183a directory typically found along a user's PATH, or in another obvious
184and convenient place.
185
186In this documentation, C<#!/usr/bin/perl> on the first line of the script
187will stand in for whatever method works on your system.
188
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189=head2 Switches
190
191A single-character switch may be combined with the following switch, if
192any.
193
194 #!/usr/bin/perl -spi.bak # same as -s -p -i.bak
195
196Switches include:
197
198=over 5
199
e0ebc809 200=item B<-0>[I<digits>]
a0d0e21e 201
55497cff 202specifies the input record separator (C<$/>) as an octal number. If there are
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203no digits, the null character is the separator. Other switches may
204precede or follow the digits. For example, if you have a version of
205B<find> which can print filenames terminated by the null character, you
206can say this:
207
208 find . -name '*.bak' -print0 | perl -n0e unlink
209
210The special value 00 will cause Perl to slurp files in paragraph mode.
5f05dabc 211The value 0777 will cause Perl to slurp files whole because there is no
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212legal character with that value.
213
214=item B<-a>
215
216turns on autosplit mode when used with a B<-n> or B<-p>. An implicit
217split command to the @F array is done as the first thing inside the
218implicit while loop produced by the B<-n> or B<-p>.
219
220 perl -ane 'print pop(@F), "\n";'
221
222is equivalent to
223
224 while (<>) {
225 @F = split(' ');
226 print pop(@F), "\n";
227 }
228
229An alternate delimiter may be specified using B<-F>.
230
231=item B<-c>
232
233causes Perl to check the syntax of the script and then exit without
cb1a09d0 234executing it. Actually, it I<will> execute C<BEGIN>, C<END>, and C<use> blocks,
54310121 235because these are considered as occurring outside the execution of
cb1a09d0 236your program.
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237
238=item B<-d>
239
240runs the script under the Perl debugger. See L<perldebug>.
241
e0ebc809 242=item B<-d:>I<foo>
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243
244runs the script under the control of a debugging or tracing module
a77489aa 245installed as Devel::foo. E.g., B<-d:DProf> executes the script using the
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246Devel::DProf profiler. See L<perldebug>.
247
db2ba183 248=item B<-D>I<letters>
a0d0e21e 249
db2ba183 250=item B<-D>I<number>
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251
252sets debugging flags. To watch how it executes your script, use
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253B<-Dtls>. (This works only if debugging is compiled into your
254Perl.) Another nice value is B<-Dx>, which lists your compiled
255syntax tree. And B<-Dr> displays compiled regular expressions. As an
256alternative, specify a number instead of list of letters (e.g., B<-D14> is
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257equivalent to B<-Dtls>):
258
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259 1 p Tokenizing and parsing
260 2 s Stack snapshots
261 4 l Context (loop) stack processing
262 8 t Trace execution
263 16 o Method and overloading resolution
264 32 c String/numeric conversions
265 64 P Print preprocessor command for -P
266 128 m Memory allocation
267 256 f Format processing
268 512 r Regular expression parsing and execution
269 1024 x Syntax tree dump
270 2048 u Tainting checks
8c52afec 271 4096 L Memory leaks (needs C<-DLEAKTEST> when compiling Perl)
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272 8192 H Hash dump -- usurps values()
273 16384 X Scratchpad allocation
274 32768 D Cleaning up
a0d0e21e 275
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276All these flags require C<-DDEBUGGING> when you compile the Perl
277executable. This flag is automatically set if you include C<-g>
278option when C<Configure> asks you about optimizer/debugger flags.
279
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280=item B<-e> I<commandline>
281
54310121 282may be used to enter one line of script.
a0d0e21e 283If B<-e> is given, Perl
54310121 284will not look for a script filename in the argument list.
a0d0e21e 285Multiple B<-e> commands may
4a6725af 286be given to build up a multi-line script.
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287Make sure to use semicolons where you would in a normal program.
288
e0ebc809 289=item B<-F>I<pattern>
a0d0e21e 290
e0ebc809 291specifies the pattern to split on if B<-a> is also in effect. The
5f05dabc 292pattern may be surrounded by C<//>, C<"">, or C<''>, otherwise it will be
e0ebc809 293put in single quotes.
a0d0e21e 294
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295=item B<-h>
296
297prints a summary of the options.
298
299=item B<-i>[I<extension>]
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300
301specifies that files processed by the C<E<lt>E<gt>> construct are to be edited
302in-place. It does this by renaming the input file, opening the output
303file by the original name, and selecting that output file as the default
304for print() statements. The extension, if supplied, is added to the name
305of the old file to make a backup copy. If no extension is supplied, no
306backup is made. From the shell, saying
307
308 $ perl -p -i.bak -e "s/foo/bar/; ... "
309
310is the same as using the script:
311
312 #!/usr/bin/perl -pi.bak
313 s/foo/bar/;
314
315which is equivalent to
316
317 #!/usr/bin/perl
318 while (<>) {
319 if ($ARGV ne $oldargv) {
320 rename($ARGV, $ARGV . '.bak');
321 open(ARGVOUT, ">$ARGV");
322 select(ARGVOUT);
323 $oldargv = $ARGV;
324 }
325 s/foo/bar/;
326 }
327 continue {
328 print; # this prints to original filename
329 }
330 select(STDOUT);
331
332except that the B<-i> form doesn't need to compare $ARGV to $oldargv to
333know when the filename has changed. It does, however, use ARGVOUT for
334the selected filehandle. Note that STDOUT is restored as the
335default output filehandle after the loop.
336
7b8d334a 337You can use C<eof> without parentheses to locate the end of each input file,
54310121 338in case you want to append to each file, or reset line numbering (see
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339example in L<perlfunc/eof>).
340
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341Finally, note that the B<-i> switch does not impede execution when no
342files are given on the command line. In this case, no backup is made
343(the original file cannot, of course, be determined) and processing
344proceeds from STDIN to STDOUT as might be expected.
345
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346=item B<-I>I<directory>
347
e0ebc809 348Directories specified by B<-I> are prepended to the search path for
1fef88e7 349modules (C<@INC>), and also tells the C preprocessor where to search for
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350include files. The C preprocessor is invoked with B<-P>; by default it
351searches /usr/include and /usr/lib/perl.
a0d0e21e 352
e0ebc809 353=item B<-l>[I<octnum>]
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354
355enables automatic line-ending processing. It has two effects: first,
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356it automatically chomps "C<$/>" (the input record separator) when used
357with B<-n> or B<-p>, and second, it assigns "C<$\>"
358(the output record separator) to have the value of I<octnum> so that
359any print statements will have that separator added back on. If
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360I<octnum> is omitted, sets "C<$\>" to the current value of "C<$/>". For
361instance, to trim lines to 80 columns:
362
363 perl -lpe 'substr($_, 80) = ""'
364
365Note that the assignment C<$\ = $/> is done when the switch is processed,
366so the input record separator can be different than the output record
367separator if the B<-l> switch is followed by a B<-0> switch:
368
369 gnufind / -print0 | perl -ln0e 'print "found $_" if -p'
370
1fef88e7 371This sets C<$\> to newline and then sets C<$/> to the null character.
a0d0e21e 372
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373=item B<-m>[B<->]I<module>
374
375=item B<-M>[B<->]I<module>
c07a80fd 376
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377=item B<-M>[B<->]I<'module ...'>
378
379=item B<-[mM]>[B<->]I<module=arg[,arg]...>
3c81428c 380
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381C<-m>I<module> executes C<use> I<module> C<();> before executing your
382script.
3c81428c 383
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384C<-M>I<module> executes C<use> I<module> C<;> before executing your
385script. You can use quotes to add extra code after the module name,
386e.g., C<-M'module qw(foo bar)'>.
3c81428c 387
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388If the first character after the C<-M> or C<-m> is a dash (C<->)
389then the 'use' is replaced with 'no'.
390
54310121 391A little builtin syntactic sugar means you can also say
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392C<-mmodule=foo,bar> or C<-Mmodule=foo,bar> as a shortcut for
393C<-M'module qw(foo bar)'>. This avoids the need to use quotes when
394importing symbols. The actual code generated by C<-Mmodule=foo,bar> is
395C<use module split(/,/,q{foo,bar})>. Note that the C<=> form
a77489aa 396removes the distinction between C<-m> and C<-M>.
3c81428c 397
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398=item B<-n>
399
400causes Perl to assume the following loop around your script, which
401makes it iterate over filename arguments somewhat like B<sed -n> or
402B<awk>:
403
404 while (<>) {
405 ... # your script goes here
406 }
407
408Note that the lines are not printed by default. See B<-p> to have
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409lines printed. If a file named by an argument cannot be opened for
410some reason, Perl warns you about it, and moves on to the next file.
411
412Here is an efficient way to delete all files older than a week:
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413
414 find . -mtime +7 -print | perl -nle 'unlink;'
415
416This is faster than using the C<-exec> switch of B<find> because you don't
417have to start a process on every filename found.
418
419C<BEGIN> and C<END> blocks may be used to capture control before or after
420the implicit loop, just as in B<awk>.
421
422=item B<-p>
423
424causes Perl to assume the following loop around your script, which
425makes it iterate over filename arguments somewhat like B<sed>:
426
427
428 while (<>) {
429 ... # your script goes here
430 } continue {
08e9d68e 431 print or die "-p destination: $!\n";
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432 }
433
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434If a file named by an argument cannot be opened for some reason, Perl
435warns you about it, and moves on to the next file. Note that the
436lines are printed automatically. An error occuring during printing is
437treated as fatal. To suppress printing use the B<-n> switch. A B<-p>
438overrides a B<-n> switch.
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439
440C<BEGIN> and C<END> blocks may be used to capture control before or after
441the implicit loop, just as in awk.
442
443=item B<-P>
444
445causes your script to be run through the C preprocessor before
5f05dabc 446compilation by Perl. (Because both comments and cpp directives begin
a0d0e21e 447with the # character, you should avoid starting comments with any words
5f05dabc 448recognized by the C preprocessor such as "if", "else", or "define".)
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449
450=item B<-s>
451
452enables some rudimentary switch parsing for switches on the command
453line after the script name but before any filename arguments (or before
454a B<-->). Any switch found there is removed from @ARGV and sets the
455corresponding variable in the Perl script. The following script
456prints "true" if and only if the script is invoked with a B<-xyz> switch.
457
458 #!/usr/bin/perl -s
459 if ($xyz) { print "true\n"; }
460
461=item B<-S>
462
463makes Perl use the PATH environment variable to search for the
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464script (unless the name of the script contains directory separators).
465On some platforms, this also makes Perl append suffixes to the
466filename while searching for it. For example, on Win32 platforms,
467the ".bat" and ".cmd" suffixes are appended if a lookup for the
468original name fails, and if the name does not already end in one
469of those suffixes. If your Perl was compiled with DEBUGGING turned
470on, using the -Dp switch to Perl shows how the search progresses.
471
a3cb178b 472If the filename supplied contains directory separators (i.e. it is an
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473absolute or relative pathname), and if the file is not found,
474platforms that append file extensions will do so and try to look
475for the file with those extensions added, one by one.
476
477On DOS-like platforms, if the script does not contain directory
478separators, it will first be searched for in the current directory
479before being searched for on the PATH. On Unix platforms, the
480script will be searched for strictly on the PATH.
481
482Typically this is used to emulate #! startup on platforms that
483don't support #!. This example works on many platforms that
484have a shell compatible with Bourne shell:
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485
486 #!/usr/bin/perl
a3cb178b 487 eval 'exec /usr/bin/perl -wS $0 ${1+"$@"}'
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488 if $running_under_some_shell;
489
490The system ignores the first line and feeds the script to /bin/sh,
491which proceeds to try to execute the Perl script as a shell script.
492The shell executes the second line as a normal shell command, and thus
493starts up the Perl interpreter. On some systems $0 doesn't always
494contain the full pathname, so the B<-S> tells Perl to search for the
495script if necessary. After Perl locates the script, it parses the
496lines and ignores them because the variable $running_under_some_shell
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497is never true. If the script will be interpreted by csh, you will need
498to replace C<${1+"$@"}> with C<$*>, even though that doesn't understand
499embedded spaces (and such) in the argument list. To start up sh rather
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500than csh, some systems may have to replace the #! line with a line
501containing just a colon, which will be politely ignored by Perl. Other
502systems can't control that, and need a totally devious construct that
5f05dabc 503will work under any of csh, sh, or Perl, such as the following:
a0d0e21e 504
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505 eval '(exit $?0)' && eval 'exec /usr/bin/perl -wS $0 ${1+"$@"}'
506 & eval 'exec /usr/bin/perl -wS $0 $argv:q'
5f05dabc 507 if $running_under_some_shell;
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508
509=item B<-T>
510
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511forces "taint" checks to be turned on so you can test them. Ordinarily
512these checks are done only when running setuid or setgid. It's a good
513idea to turn them on explicitly for programs run on another's behalf,
514such as CGI programs. See L<perlsec>. Note that (for security reasons)
515this option must be seen by Perl quite early; usually this means it must
516appear early on the command line or in the #! line (for systems which
517support that).
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518
519=item B<-u>
520
521causes Perl to dump core after compiling your script. You can then
5a964f20 522in theory take this core dump and turn it into an executable file by using the
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523B<undump> program (not supplied). This speeds startup at the expense of
524some disk space (which you can minimize by stripping the executable).
525(Still, a "hello world" executable comes out to about 200K on my
526machine.) If you want to execute a portion of your script before dumping,
527use the dump() operator instead. Note: availability of B<undump> is
528platform specific and may not be available for a specific port of
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529Perl. It has been superseded by the new perl-to-C compiler, which is more
530portable, even though it's still only considered beta.
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531
532=item B<-U>
533
534allows Perl to do unsafe operations. Currently the only "unsafe"
535operations are the unlinking of directories while running as superuser,
536and running setuid programs with fatal taint checks turned into
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537warnings. Note that the B<-w> switch (or the C<$^W> variable) must
538be used along with this option to actually B<generate> the
539taint-check warnings.
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540
541=item B<-v>
542
543prints the version and patchlevel of your Perl executable.
544
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545=item B<-V>
546
547prints summary of the major perl configuration values and the current
548value of @INC.
549
e0ebc809 550=item B<-V:>I<name>
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551
552Prints to STDOUT the value of the named configuration variable.
553
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554=item B<-w>
555
049cd8b0 556prints warnings about variable names that are mentioned only once, and
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557scalar variables that are used before being set. Also warns about
558redefined subroutines, and references to undefined filehandles or
5f05dabc 559filehandles opened read-only that you are attempting to write on. Also
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560warns you if you use values as a number that doesn't look like numbers,
561using an array as though it were a scalar, if your subroutines recurse
562more than 100 deep, and innumerable other things.
563
564You can disable specific warnings using C<__WARN__> hooks, as described
565in L<perlvar> and L<perlfunc/warn>. See also L<perldiag> and L<perltrap>.
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566
567=item B<-x> I<directory>
568
569tells Perl that the script is embedded in a message. Leading
570garbage will be discarded until the first line that starts with #! and
571contains the string "perl". Any meaningful switches on that line will
ff0cee69 572be applied. If a directory name is specified, Perl will switch to
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573that directory before running the script. The B<-x> switch controls
574only the disposal of leading garbage. The script must be
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575terminated with C<__END__> if there is trailing garbage to be ignored (the
576script can process any or all of the trailing garbage via the DATA
577filehandle if desired).
578
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579=back
580
581=head1 ENVIRONMENT
582
583=over 12
584
585=item HOME
586
587Used if chdir has no argument.
588
589=item LOGDIR
590
591Used if chdir has no argument and HOME is not set.
592
593=item PATH
594
595Used in executing subprocesses, and in finding the script if B<-S> is
596used.
597
598=item PERL5LIB
599
600A colon-separated list of directories in which to look for Perl library
601files before looking in the standard library and the current
602directory. If PERL5LIB is not defined, PERLLIB is used. When running
603taint checks (because the script was running setuid or setgid, or the
604B<-T> switch was used), neither variable is used. The script should
605instead say
606
607 use lib "/my/directory";
608
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609=item PERL5OPT
610
611Command-line options (switches). Switches in this variable are taken
612as if they were on every Perl command line. Only the B<-[DIMUdmw]>
613switches are allowed. When running taint checks (because the script
614was running setuid or setgid, or the B<-T> switch was used), this
615variable is ignored.
616
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617=item PERLLIB
618
619A colon-separated list of directories in which to look for Perl library
620files before looking in the standard library and the current directory.
621If PERL5LIB is defined, PERLLIB is not used.
622
623=item PERL5DB
624
625The command used to load the debugger code. The default is:
626
627 BEGIN { require 'perl5db.pl' }
628
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629=item PERL5SHELL (specific to WIN32 port)
630
631May be set to an alternative shell that perl must use internally for
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632executing "backtick" commands or system(). Default is C<cmd.exe /x/c>
633on WindowsNT and C<command.com /c> on Windows95. The value is considered
634to be space delimited. Precede any character that needs to be protected
635(like a space or backslash) with a backslash.
636
637Note that Perl doesn't use COMSPEC for this purpose because
638COMSPEC has a high degree of variability among users, leading to
639portability concerns. Besides, perl can use a shell that may not be
640fit for interactive use, and setting COMSPEC to such a shell may
641interfere with the proper functioning of other programs (which usually
642look in COMSPEC to find a shell fit for interactive use).
174c211a 643
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644=item PERL_DEBUG_MSTATS
645
67ce8856 646Relevant only if perl is compiled with the malloc included with the perl
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647distribution (that is, if C<perl -V:d_mymalloc> is 'define').
648If set, this causes memory statistics to be dumped after execution. If set
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649to an integer greater than one, also causes memory statistics to be dumped
650after compilation.
651
652=item PERL_DESTRUCT_LEVEL
653
654Relevant only if your perl executable was built with B<-DDEBUGGING>,
655this controls the behavior of global destruction of objects and other
656references.
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657
658=back
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659
660Perl also has environment variables that control how Perl handles data
661specific to particular natural languages. See L<perllocale>.
662
663Apart from these, Perl uses no other environment variables, except
664to make them available to the script being executed, and to child
665processes. However, scripts running setuid would do well to execute
666the following lines before doing anything else, just to keep people
667honest:
668
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669 $ENV{PATH} = '/bin:/usr/bin'; # or whatever you need
670 $ENV{SHELL} = '/bin/sh' if exists $ENV{SHELL};
c90c0ff4 671 delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};
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