summaryrefslogtreecommitdiff
path: root/jni/ruby/man/ruby.1
blob: c35f1305579ef69388e4868398f5fbfaa96e8b3f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
.\"Ruby is copyrighted by Yukihiro Matsumoto <matz@netlab.jp>.
.Dd November 7, 2012
.Dt RUBY(1) "" "Ruby Programmers Reference Guide"
.\".Dt RUBY 1
.Os UNIX
.Sh NAME
.Nm ruby
.Nd Interpreted object-oriented scripting language
.Sh SYNOPSIS
.Nm
.Op Fl -copyright
.Op Fl -version
.Op Fl SUacdlnpswvy
.Op Fl 0 Ns Op Ar octal
.Op Fl C Ar directory
.Op Fl E Ar external Ns Op : Ns Ar internal
.Op Fl F Ar pattern
.Op Fl I Ar directory
.Op Fl K Ar c
.Op Fl T Ns Op Ar level
.Op Fl W Ns Op Ar level
.Op Fl e Ar command
.Op Fl i Ns Op Ar extension
.Op Fl r Ar library
.Op Fl x Ns Op Ar directory
.Op - Ns Bro Cm enable Ns | Ns Cm disable Brc Ns - Ns Ar FEATURE
.Op Fl -dump Ns = Ns Ar target
.Op Fl -verbose
.Op Fl -
.Op Ar program_file
.Op Ar argument ...
.Sh DESCRIPTION
Ruby is an interpreted scripting language for quick and easy
object-oriented programming.  It has many features to process text
files and to do system management tasks (like in Perl).  It is simple,
straight-forward, and extensible.
.Pp
If you want a language for easy object-oriented programming, or you
don't like the Perl ugliness, or you do like the concept of LISP, but
don't like too many parentheses, Ruby might be your language of
choice.
.Sh FEATURES
Ruby's features are as follows:
.Bl -tag -width 6n
.It Sy "Interpretive"
Ruby is an interpreted language, so you don't have to recompile
programs written in Ruby to execute them.
.Pp
.It Sy "Variables have no type (dynamic typing)"
Variables in Ruby can contain data of any type.  You don't have to
worry about variable typing.  Consequently, it has a weaker compile
time check.
.Pp
.It Sy "No declaration needed"
You can use variables in your Ruby programs without any declarations.
Variable names denote their scope - global, class, instance, or local.
.Pp
.It Sy "Simple syntax"
Ruby has a simple syntax influenced slightly from Eiffel.
.Pp
.It Sy "No user-level memory management"
Ruby has automatic memory management.  Objects no longer referenced
from anywhere are automatically collected by the garbage collector
built into the interpreter.
.Pp
.It Sy "Everything is an object"
Ruby is a purely object-oriented language, and was so since its
creation.  Even such basic data as integers are seen as objects.
.Pp
.It Sy "Class, inheritance, and methods"
Being an object-oriented language, Ruby naturally has basic
features like classes, inheritance, and methods.
.Pp
.It Sy "Singleton methods"
Ruby has the ability to define methods for certain objects.  For
example, you can define a press-button action for certain widget by
defining a singleton method for the button.  Or, you can make up your
own prototype based object system using singleton methods, if you want
to.
.Pp
.It Sy "Mix-in by modules"
Ruby intentionally does not have the multiple inheritance as it is a
source of confusion.  Instead, Ruby has the ability to share
implementations across the inheritance tree.  This is often called a
.Sq Mix-in .
.Pp
.It Sy "Iterators"
Ruby has iterators for loop abstraction.
.Pp
.It Sy "Closures"
In Ruby, you can objectify the procedure.
.Pp
.It Sy "Text processing and regular expressions"
Ruby has a bunch of text processing features like in Perl.
.Pp
.It Sy "M17N, character set independent"
Ruby supports multilingualized programming. Easy to process texts
written in many different natural languages and encoded in many
different character encodings, without dependence on Unicode.
.Pp
.It Sy "Bignums"
With built-in bignums, you can for example calculate factorial(400).
.Pp
.It Sy "Reflection and domain specific languages"
Class is also an instance of the Class class. Definition of classes and methods
is an expression just as 1+1 is. So your programs can even write and modify programs.
Thus you can write your application in your own programming language on top of Ruby.
.Pp
.It Sy "Exception handling"
As in Java(tm).
.Pp
.It Sy "Direct access to the OS"
Ruby can use most
.Ux
system calls, often used in system programming.
.Pp
.It Sy "Dynamic loading"
On most
.Ux
systems, you can load object files into the Ruby interpreter
on-the-fly.
.It Sy "Rich libraries"
Libraries called "builtin libraries" and "standard libraries" are bundled with Ruby.
And you can obtain more libraries via the package management system called `RubyGems'.
.Pp
Moreover there are thousands of Ruby projects on GitHub
.Aq Pa https://github.com/languages/Ruby .
.El
.Pp
.Sh OPTIONS
Ruby interpreter accepts following command-line options (switches).
They are quite similar to those of
.Xr perl 1 .
.Bl -tag -width "1234567890123" -compact
.Pp
.It Fl -copyright
Prints the copyright notice.
.Pp
.It Fl -version
Prints the version of Ruby interpreter.
.Pp
.It Fl 0 Ns Op Ar octal
(The digit
.Dq zero . )
Specifies the input record separator
.Pf ( Li "$/" )
as an octal number. If no digit is given, the null character is taken
as the separator.  Other switches may follow the digits.
.Fl 00
turns Ruby into paragraph mode.
.Fl 0777
makes Ruby read whole file at once as a single string since there is
no legal character with that value.
.Pp
.It Fl C Ar directory
.It Fl X Ar directory
Causes Ruby to switch to the directory.
.Pp
.It Fl E Ar external Ns Op : Ns Ar internal
.It Fl -encoding Ar external Ns Op : Ns Ar internal
Specifies the default value(s) for external encodings and internal encoding. Values should be separated with colon (:).
.Pp
You can omit the one for internal encodings, then the value
.Pf ( Li "Encoding.default_internal" ) will be nil.
.Pp
.It Fl -external-encoding Ns = Ns Ar encoding
.It Fl -internal-encoding Ns = Ns Ar encoding
Specify the default external or internal character encoding
.Pp
.It Fl F Ar pattern
Specifies input field separator
.Pf ( Li "$;" ) .
.Pp
.It Fl I Ar directory
Used to tell Ruby where to load the library scripts.  Directory path
will be added to the load-path variable
.Pf ( Li "$:" ) .
.Pp
.It Fl K Ar kcode
Specifies KANJI (Japanese) encoding. The default value for script encodings
.Pf ( Li "__ENCODING__" ) and external encodings ( Li "Encoding.default_external" ) will be the specified one.
.Ar kcode
can be one of
.Bl -hang -offset indent
.It Sy e
EUC-JP
.Pp
.It Sy s
Windows-31J (CP932)
.Pp
.It Sy u
UTF-8
.Pp
.It Sy n
ASCII-8BIT (BINARY)
.El
.Pp
.It Fl S
Makes Ruby use the
.Ev PATH
environment variable to search for script, unless its name begins
with a slash.  This is used to emulate
.Li #!
on machines that don't support it, in the following manner:
.Bd -literal -offset indent
#! /usr/local/bin/ruby
# This line makes the next one a comment in Ruby \e
  exec /usr/local/bin/ruby -S $0 $*
.Ed
.Pp
.It Fl T Ns Op Ar level=1
Turns on taint checks at the specified level (default 1).
.Pp
.It Fl U
Sets the default value for internal encodings
.Pf ( Li "Encoding.default_internal" ) to UTF-8.
.Pp
.It Fl W Ns Op Ar level=2
Turns on verbose mode at the specified level without printing the version
message at the beginning. The level can be;
.Bl -hang -offset indent
.It Sy 0
Verbose mode is "silence". It sets the
.Li "$VERBOSE"
to nil.
.Pp
.It Sy 1
Verbose mode is "medium". It sets the
.Li "$VERBOSE"
to false.
.Pp
.It Sy 2 (default)
Verbose mode is "verbose". It sets the
.Li "$VERBOSE"
to true.
.Fl W Ns
2 is same as
.Fl w
.
.El
.Pp
.It Fl a
Turns on auto-split mode when used with
.Fl n
or
.Fl p .
In auto-split mode, Ruby executes
.Dl $F = $_.split
at beginning of each loop.
.Pp
.It Fl c
Causes Ruby to check the syntax of the script and exit without
executing. If there are no syntax errors, Ruby will print
.Dq Syntax OK
to the standard output.
.Pp
.It Fl d
.It Fl -debug
Turns on debug mode.
.Li "$DEBUG"
will be set to true.
.Pp
.It Fl e Ar command
Specifies script from command-line while telling Ruby not to search
the rest of the arguments for a script file name.
.Pp
.It Fl h
.It Fl -help
Prints a summary of the options.
.Pp
.It Fl i Ar extension
Specifies in-place-edit mode.  The extension, if specified, is added
to old file name to make a backup copy.  For example:
.Bd -literal -offset indent
% echo matz > /tmp/junk
% cat /tmp/junk
matz
% ruby -p -i.bak -e '$_.upcase!' /tmp/junk
% cat /tmp/junk
MATZ
% cat /tmp/junk.bak
matz
.Ed
.Pp
.It Fl l
(The lowercase letter
.Dq ell . )
Enables automatic line-ending processing, which means to firstly set
.Li "$\e"
to the value of
.Li "$/" ,
and secondly chops every line read using
.Li chop! .
.Pp
.It Fl n
Causes Ruby to assume the following loop around your script, which
makes it iterate over file name arguments somewhat like
.Nm sed
.Fl n
or
.Nm awk .
.Bd -literal -offset indent
while gets
  ...
end
.Ed
.Pp
.It Fl p
Acts mostly same as -n switch, but print the value of variable
.Li "$_"
at the each end of the loop.  For example:
.Bd -literal -offset indent
% echo matz | ruby -p -e '$_.tr! "a-z", "A-Z"'
MATZ
.Ed
.Pp
.It Fl r Ar library
Causes Ruby to load the library using require.  It is useful when using
.Fl n
or
.Fl p .
.Pp
.It Fl s
Enables some switch parsing for switches after script name but before
any file name arguments (or before a
.Fl - ) .
Any switches found there are removed from
.Li ARGV
and set the corresponding variable in the script.  For example:
.Bd -literal -offset indent
#! /usr/local/bin/ruby -s
# prints "true" if invoked with `-xyz' switch.
print "true\en" if $xyz
.Ed
.Pp
On some systems
.Li "$0"
does not always contain the full pathname, so you need the
.Fl S
switch to tell Ruby to search for the script if necessary (to handle embedded
spaces and such).  A better construct than
.Li "$*"
would be
.Li ${1+"$@"} ,
but it does not work if the script is being interpreted by
.Xr csh 1 .
.Pp
.It Fl v
Enables verbose mode.  Ruby will print its version at the beginning
and set the variable
.Li "$VERBOSE"
to true.  Some methods print extra messages if this variable is true.
If this switch is given, and no other switches are present, Ruby quits
after printing its version.
.Pp
.It Fl w
Enables verbose mode without printing version message at the
beginning.  It sets the
.Li "$VERBOSE"
variable to true.
.Pp
.It Fl x Ns Op Ar directory
Tells Ruby that the script is embedded in a message.  Leading garbage
will be discarded until the first line that starts with
.Dq #!
and contains the string,
.Dq ruby .
Any meaningful switches on that line will be applied.  The end of the script
must be specified with either
.Li EOF ,
.Li "^D" ( Li "control-D" ) ,
.Li "^Z" ( Li "control-Z" ) ,
or the reserved word
.Li __END__ .
If the directory name is specified, Ruby will switch to that directory
before executing script.
.Pp
.It Fl y
.It Fl -yydebug
DO NOT USE.
.Pp
Turns on compiler debug mode.  Ruby will print a bunch of internal
state messages during compilation.  Only specify this switch you are going to
debug the Ruby interpreter.
.Pp
.It Fl -disable- Ns Ar FEATURE
.It Fl -enable- Ns Ar FEATURE
Disables (or enables) the specified
.Ar FEATURE Ns
\&.
.Bl -tag -width "--disable-rubyopt" -compact
.It Fl -disable-gems
.It Fl -enable-gems
Disables (or enables) RubyGems libraries.  By default, Ruby will load the latest
version of each installed gem. The
.Li Gem
constant is true if RubyGems is enabled, false if otherwise.
.Pp
.It Fl -disable-rubyopt
.It Fl -enable-rubyopt
Ignores (or considers) the
.Ev RUBYOPT
environment variable. By default, Ruby considers the variable.
.Pp
.It Fl -disable-all
.It Fl -enable-all
Disables (or enables) all features.
.Pp
.El
.Pp
.It Fl -dump Ns = Ns Ar target
DO NOT USE.
.Pp
Prints the specified target.
.Ar target
can be one of;
.Bl -hang -offset indent
.It Sy insns
disassembled instructions
.Pp
.El
.Pp
Only specify this switch if you are going to debug the Ruby interpreter.
.Pp
.It Fl -verbose
Enables verbose mode without printing version message at the
beginning.  It sets the
.Li "$VERBOSE"
variable to true.
If this switch is given, and no other switches are present, Ruby quits
after printing its version.
.El
.Pp
.Sh ENVIRONMENT
.Bl -tag -width "RUBYSHELL" -compact
.It Ev RUBYLIB
A colon-separated list of directories that are added to Ruby's
library load path
.Pf ( Li "$:" ) . Directories from this environment variable are searched
before the standard load path is searched.
.Pp
e.g.:
.Dl RUBYLIB="$HOME/lib/ruby:$HOME/lib/rubyext"
.Pp
.It Ev RUBYOPT
Additional Ruby options.
.Pp
e.g.
.Dl RUBYOPT="-w -Ke"
.Pp
Note that RUBYOPT can contain only
.Fl d , Fl E , Fl I , Fl K , Fl r , Fl T , Fl U , Fl v , Fl w , Fl W, Fl -debug ,
.Fl -disable- Ns Ar FEATURE
and
.Fl -enable- Ns Ar FEATURE .
.Pp
.It Ev RUBYPATH
A colon-separated list of directories that Ruby searches for
Ruby programs when the
.Fl S
flag is specified.  This variable precedes the
.Ev PATH
environment variable.
.Pp
.It Ev RUBYSHELL
The path to the system shell command.  This environment variable is
enabled for only mswin32, mingw32, and OS/2 platforms.  If this
variable is not defined, Ruby refers to
.Ev COMSPEC .
.Pp
.It Ev PATH
Ruby refers to the
.Ev PATH
environment variable on calling Kernel#system.
.El
.Pp
And Ruby depends on some RubyGems related environment variables unless RubyGems is disabled.
See the help of
.Xr gem 1
as below.
.Bd -literal -offset indent
% gem help
.Ed
.Pp
.Sh GC ENVIRONMENT
The Ruby garbage collector (GC) tracks objects in fixed-sized slots,
but each object may have auxillary memory allocations handled by the
malloc family of C standard library calls (
.Xr malloc 3 ,
.Xr calloc 3 ,
and
.Xr realloc 3 ) .
In this documentatation, the "heap" refers to the Ruby object heap
of fixed-sized slots, while "malloc" refers to auxillary
allocations commonly referred to as the "process heap".
Thus there are at least two possible ways to trigger GC:
.Bl -hang -offset indent
.It Sy 1
Reaching the object limit.
.It Sy 2
Reaching the malloc limit.
.Pp
.El
In Ruby 2.1, the generational GC was introduced and the limits are divided
into young and old generations, providing two additional ways to trigger
a GC:
.Bl -hang -offset indent
.It Sy 3
Reaching the old object limit.
.It Sy 4
Reaching the old malloc limit.
.El
.Pp
There are currently 4 possible areas where the GC may be tuned by
the the following 11 environment variables:
.Bl -hang -compact -width "RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR"
.It Ev RUBY_GC_HEAP_INIT_SLOTS
Initial allocation slots.  Introduced in Ruby 2.1, default: 10000.
.Pp
.It Ev RUBY_GC_HEAP_FREE_SLOTS
Prepare at least this amount of slots after GC.
Allocate this number slots if there are not enough slots.
Introduced in Ruby 2.1, default: 4096
.Pp
.It Ev RUBY_GC_HEAP_GROWTH_FACTOR
Increase allocation rate of heap slots by this factor.
Introduced in Ruby 2.1, default: 1.8, minimum: 1.0 (no growth)
.Pp
.It Ev RUBY_GC_HEAP_GROWTH_MAX_SLOTS
Allocation rate is limited to this number of slots,
preventing excessive allocation due to RUBY_GC_HEAP_GROWTH_FACTOR.
Introduced in Ruby 2.1, default: 0 (no limit)
.Pp
.It Ev RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR
Perform a full GC when the number of old objects is more than R * N,
where R is this factor and N is the number of old objects after the
last full GC.
Introduced in Ruby 2.1.1, default: 2.0
.Pp
.It Ev RUBY_GC_MALLOC_LIMIT
The initial limit of young generation allocation from the malloc-family.
GC will start when this limit is reached.
Default: 16MB
.Pp
.It Ev RUBY_GC_MALLOC_LIMIT_MAX
The maximum limit of young generation allocation from malloc before GC starts.
Prevents excessive malloc growth due to RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR.
Introduced in Ruby 2.1, default: 32MB.
.Pp
.It Ev RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR
Increases the limit of young generation malloc calls, reducing
GC frequency but increasing malloc growth until RUBY_GC_MALLOC_LIMIT_MAX
is reached.
Introduced in Ruby 2.1, default: 1.4, minimum: 1.0 (no growth)
.Pp
.It Ev RUBY_GC_OLDMALLOC_LIMIT
The initial limit of old generation allocation from malloc,
a full GC will start when this limit is reached.
Introduced in Ruby 2.1, default: 16MB
.Pp
.It Ev RUBY_GC_OLDMALLOC_LIMIT_MAX
The maximum limit of old generation allocation from malloc before a
full GC starts.
Prevents excessive malloc growth due to RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR.
Introduced in Ruby 2.1, default: 128MB
.Pp
.It Ev RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR
Increases the limit of old generation malloc allocation, reducing full
GC frequency but increasing malloc growth until RUBY_GC_OLDMALLOC_LIMIT_MAX
is reached.
Introduced in Ruby 2.1, default: 1.2, minimum: 1.0 (no growth)
.Pp
.El
.Sh STACK SIZE ENVIRONMENT
Stack size environment variables are implementation-dependent and
subject to change with different versions of Ruby.  The VM stack is used
for pure-Ruby code and managed by the virtual machine.  Machine stack is
used by the operating system and its usage is dependent on C extensions
as well as C compiler options.  Using lower values for these may allow
applications to keep more Fibers or Threads running; but increases the
chance of SystemStackError exceptions and segmentation faults (SIGSEGV).
These environment variables are available since Ruby 2.0.0.
All values are specified in bytes.
.Pp
.Bl -hang -compact -width "RUBY_THREAD_MACHINE_STACK_SIZE"
.It Ev RUBY_THREAD_VM_STACK_SIZE
VM stack size used at thread creation.
default: 131072 (32-bit CPU) or 262144 (64-bit)
.Pp
.It Ev RUBY_THREAD_MACHINE_STACK_SIZE
Machine stack size used at thread creation.
default: 524288 or 1048575
.Pp
.It Ev RUBY_FIBER_VM_STACK_SIZE
VM stack size used at fiber creation.
default: 65536 or 131072
.Pp
.It Ev RUBY_FIBER_MACHINE_STACK_SIZE
Machine stack size used at fiber creation.
default: 262144 or 524288
.Pp
.El
.Sh SEE ALSO
.Bl -hang -compact -width "http://www.ruby-lang.org/123"
.It https://www.ruby-lang.org/
The official web site.
.It https://www.ruby-toolbox.com/
Comprehensive catalog of Ruby libraries.
.El
.Pp
.Sh REPORTING BUGS
.Bl -bullet
.Li Security vulnerabilities should be reported via an email to
.Aq security@ruby-lang.org Ns
.Li .
Reported problems will be published after they've been fixed.
.Pp
.Li And you can report other bugs and feature requests via the
Ruby Issue Tracking System (https://bugs.ruby-lang.org/).
Do not report security vulnerabilities
via the system because it publishes the vulnerabilities immediately.
.El
.Sh AUTHORS
Ruby is designed and implemented by
.An Yukihiro Matsumoto Aq matz@netlab.jp .
.Pp
See
.Aq Pa https://bugs.ruby-lang.org/projects/ruby/wiki/Contributors
for contributors to Ruby.