src/env_parallel.pod

   1 #!/usr/bin/perl -w
   2
   3 # SPDX-FileCopyrightText: 2021-2024 Ole Tange, http://ole.tange.dk and Free Software and Foundation, Inc.
   4 # SPDX-License-Identifier: GFDL-1.3-or-later
   5 # SPDX-License-Identifier: CC-BY-SA-4.0
   6
   7 =encoding utf8
   8
   9 =head1 NAME
  10
  11 env_parallel - export environment to GNU parallel
  12
  13
  14 =head1 SYNOPSIS
  15
  16 B<env_parallel> [--record-env|--session|--end-session]
  17   [options for GNU Parallel]
  18
  19
  20 =head1 DESCRIPTION
  21
  22 B<env_parallel> is a shell function that exports the current
  23 environment to GNU B<parallel>.
  24
  25 If the shell function is not loaded, a dummy script will be run
  26 instead that explains how to install the function.
  27
  28 B<env_parallel> is 100 ms slower at startup than pure GNU B<parallel>,
  29 and takes up to 30% longer to start a job (typically 15 ms).
  30
  31 Due to the problem with environment space (see below) you are
  32 recommended only to transfer the environment that you need.
  33
  34 To help you do that, you can mark names that should not be
  35 transferred. This can be done with either B<--session> or
  36 B<--record-env>.
  37
  38   # Record the "clean" environment (this only needs to be run once)
  39   env_parallel --record-env
  40
  41   # Optionally edit ~/.parallel/ignored_vars (only needed once)
  42
  43   # Define whatever you want to use
  44   myfunc() { myalias and functions $myvar work. $1.; }
  45   alias myalias='echo Aliases'
  46   myvar='and variables'
  47
  48   # Use --env _ to only transfer the names not in the "empty" environment
  49   env_parallel --env _ -S localhost myfunc ::: Hooray
  50
  51 Or:
  52
  53   # Do --record-env into $PARALLEL_IGNORED_NAMES
  54   env_parallel --session
  55
  56   # Define whatever you want to use
  57   myfunc() { myalias and functions $myvar work. $1.; }
  58   alias myalias='echo Aliases'
  59   myvar='and variables'
  60
  61   # env_parallel will not export names in $PARALLEL_IGNORED_NAMES
  62   env_parallel -S localhost myfunc ::: Hooray
  63
  64   # Optionally
  65   env_parallel --end-session
  66
  67 In B<csh> B<--session> is not supported:
  68
  69   # Record the "clean" environment - this only needs to be run once
  70   env_parallel --record-env
  71
  72   # Optionally edit ~/.parallel/ignored_vars - only needed once
  73
  74   # Define whatever you want to use
  75   alias myalias 'echo Aliases $myvar \!*.'
  76   set myvar='and variables'
  77
  78   # Use --env _ to only transfer the names not in the "empty" environment
  79   env_parallel --env _ -S localhost myalias ::: work
  80
  81 =head2 Environment space
  82
  83 By default B<env_parallel> will export all environment variables,
  84 arrays, aliases, functions and shell options (see details for the
  85 individual shells below).
  86
  87 But this only works if the size of the current environment is smaller
  88 than the maximal length of a command and smaller than half of the max
  89 if running remotely. E.g. The max size of Bash's command is 128 KB, so
  90 B<env_parallel> will fail if 'B<set | wc -c>' is bigger than 128
  91 KB. Technically the limit is in execve(1) which IPC::open3 uses.
  92
  93 Bash completion functions are well-known for taking up well over 128
  94 KB of environment space and the primary reason for causing
  95 B<env_parallel> to fail.
  96
  97 Instead you can use B<--env> to specify which variables, arrays,
  98 aliases and functions to export as this will only export those with
  99 the given name. Or follow the recommended usage in shown in
 100 DESCRIPTION.
 101
 102
 103 =head1 OPTIONS
 104
 105 Same as GNU B<parallel> in addition to these:
 106
 107 =over 4
 108
 109 =item B<--end-session>
 110
 111 Undo last B<--session>
 112
 113
 114 =item B<--record-env>
 115
 116 Record all names currently defined to be ignored every time running
 117 B<env_parallel> in the future.
 118
 119
 120 =item B<--session>
 121
 122 Ignore all names currently defined. Aliases, variables, arrays, and
 123 functions currently defined will not be transferred.
 124
 125 But names defined I<after> running B<parallel --session> I<will> be
 126 transferred.
 127
 128 This is only valid in the running shell, and can be undone with
 129 B<parallel --end-session>.
 130
 131 You can run multiple B<--session> inside each other:
 132
 133   env_parallel --session
 134   var=not
 135   # var is transferred
 136   env_parallel -Slocalhost 'echo var is $var' ::: ignored
 137   env_parallel --session
 138   # var is not transferred
 139   env_parallel -Slocalhost 'echo var is $var' ::: ignored
 140   env_parallel --end-session
 141   # var is transferred again
 142   env_parallel -Slocalhost 'echo var is $var' ::: ignored
 143
 144
 145
 146 =back
 147
 148
 149 =head1 SUPPORTED SHELLS
 150
 151 =head2 Ash
 152
 153 =head3 Installation
 154
 155 Put this in $HOME/.profile:
 156
 157   . env_parallel.ash
 158
 159 E.g. by doing:
 160
 161   echo '. env_parallel.ash' >> $HOME/.profile
 162
 163 =head3 Supported use
 164
 165 B<--env> is supported to export only the variable, or alias with the
 166 given name. Multiple B<--env>s can be given.
 167
 168 B<--session> is supported.
 169
 170 =over 8
 171
 172 =item aliases
 173
 174   alias myecho='echo aliases'
 175   env_parallel myecho ::: work
 176   env_parallel -S server myecho ::: work
 177   env_parallel --env myecho myecho ::: work
 178   env_parallel --env myecho -S server myecho ::: work
 179
 180   alias multiline='echo multiline
 181     echo aliases'
 182   env_parallel multiline ::: work
 183   env_parallel -S server multiline ::: work
 184   env_parallel --env multiline multiline ::: work
 185   env_parallel --env multiline -S server multiline ::: work
 186
 187 =item functions
 188
 189   ash cannot list defined functions - thus is not supported.
 190
 191 =item variables
 192
 193   myvar=variables
 194   env_parallel echo '$myvar' ::: work
 195   env_parallel -S server echo '$myvar' ::: work
 196   env_parallel --env myvar echo '$myvar' ::: work
 197   env_parallel --env myvar -S server echo '$myvar' ::: work
 198
 199 =item arrays
 200
 201 Arrays are not supported by Ash.
 202
 203 =back
 204
 205 =head2 Bash
 206
 207 =head3 Installation
 208
 209 Put this in $HOME/.bashrc:
 210
 211   . env_parallel.bash
 212
 213 E.g. by doing:
 214
 215   echo '. env_parallel.bash' >> $HOME/.bashrc
 216
 217 =head3 Supported use
 218
 219 B<--env> is supported to export only the variable, alias, function, or
 220 array with the given name. Multiple B<--env>s can be given.
 221
 222 B<--session> is supported.
 223
 224 =over 8
 225
 226 =item aliases
 227
 228   alias myecho='echo aliases'
 229   env_parallel myecho ::: work
 230   env_parallel -S server myecho ::: work
 231   env_parallel --env myecho myecho ::: work
 232   env_parallel --env myecho -S server myecho ::: work
 233
 234   alias multiline='echo multiline
 235     echo aliases'
 236   env_parallel 'multiline {};
 237     echo but only when followed by a newline' ::: work
 238   env_parallel -S server 'multiline {};
 239     echo but only when followed by a newline' ::: work
 240   env_parallel --env multiline 'multiline {};
 241     echo but only when followed by a newline' ::: work
 242   env_parallel --env multiline -S server 'multiline {};
 243     echo but only when followed by a newline' ::: work
 244
 245 =item functions
 246
 247   myfunc() { echo functions $*; }
 248   env_parallel myfunc ::: work
 249   env_parallel -S server myfunc ::: work
 250   env_parallel --env myfunc myfunc ::: work
 251   env_parallel --env myfunc -S server myfunc ::: work
 252
 253 =item variables
 254
 255   myvar=variables
 256   env_parallel echo '$myvar' ::: work
 257   env_parallel -S server echo '$myvar' ::: work
 258   env_parallel --env myvar echo '$myvar' ::: work
 259   env_parallel --env myvar -S server echo '$myvar' ::: work
 260
 261 =item arrays
 262
 263   myarray=(arrays work, too)
 264   env_parallel -k echo '${myarray[{}]}' ::: 0 1 2
 265   env_parallel -k -S server echo '${myarray[{}]}' ::: 0 1 2
 266   env_parallel -k --env myarray echo '${myarray[{}]}' ::: 0 1 2
 267   env_parallel -k --env myarray -S server \
 268     echo '${myarray[{}]}' ::: 0 1 2
 269
 270 =back
 271
 272 =head3 BUGS
 273
 274 Due to a bug in Bash, aliases containing newlines must be followed by
 275 a newline in the command. Some systems are not affected by this bug,
 276 but will print a warning anyway.
 277
 278 =head2 csh
 279
 280 B<env_parallel> for B<csh> breaks B<$PARALLEL>, so do not use
 281 B<$PARALLEL>.
 282
 283 =head3 Installation
 284
 285 Put this in $HOME/.cshrc:
 286
 287   source `which env_parallel.csh`
 288
 289 E.g. by doing:
 290
 291   echo 'source `which env_parallel.csh`' >> $HOME/.cshrc
 292
 293 =head3 Supported use
 294
 295 B<--env> is supported to export only the variable, alias, or
 296 array with the given name. Multiple B<--env>s can be given.
 297
 298 =over 8
 299
 300 =item aliases
 301
 302   alias myecho 'echo aliases'
 303   env_parallel myecho ::: work
 304   env_parallel -S server myecho ::: work
 305   env_parallel --env myecho myecho ::: work
 306   env_parallel --env myecho -S server myecho ::: work
 307
 308 =item functions
 309
 310 Not supported by B<csh>.
 311
 312 =item variables
 313
 314   set myvar=variables
 315   env_parallel echo '$myvar' ::: work
 316   env_parallel -S server echo '$myvar' ::: work
 317   env_parallel --env myvar echo '$myvar' ::: work
 318   env_parallel --env myvar -S server echo '$myvar' ::: work
 319
 320 =item arrays with no special chars
 321
 322   set myarray=(arrays work, too)
 323   env_parallel -k echo \$'{myarray[{}]}' ::: 1 2 3
 324   env_parallel -k -S server echo \$'{myarray[{}]}' ::: 1 2 3
 325   env_parallel -k --env myarray echo \$'{myarray[{}]}' ::: 1 2 3
 326   env_parallel -k --env myarray -S server \
 327     echo \$'{myarray[{}]}' ::: 1 2 3
 328
 329 =back
 330
 331
 332 =head2 Dash
 333
 334 =head3 Installation
 335
 336 Put this in $HOME/.profile:
 337
 338   . env_parallel.dash
 339
 340 E.g. by doing:
 341
 342   echo '. env_parallel.dash' >> $HOME/.profile
 343
 344 =head3 Supported use
 345
 346 B<--env> is supported to export only the variable, or alias with the
 347 given name. Multiple B<--env>s can be given.
 348
 349 B<--session> is supported.
 350
 351 =over 8
 352
 353 =item aliases
 354
 355   alias myecho='echo aliases'
 356   env_parallel myecho ::: work
 357   env_parallel -S server myecho ::: work
 358   env_parallel --env myecho myecho ::: work
 359   env_parallel --env myecho -S server myecho ::: work
 360
 361   alias multiline='echo multiline
 362     echo aliases'
 363   env_parallel multiline ::: work
 364   env_parallel -S server multiline ::: work
 365   env_parallel --env multiline multiline ::: work
 366   env_parallel --env multiline -S server multiline ::: work
 367
 368 =item functions
 369
 370   dash cannot list defined functions - thus is not supported.
 371
 372 =item variables
 373
 374   myvar=variables
 375   env_parallel echo '$myvar' ::: work
 376   env_parallel -S server echo '$myvar' ::: work
 377   env_parallel --env myvar echo '$myvar' ::: work
 378   env_parallel --env myvar -S server echo '$myvar' ::: work
 379
 380 =item arrays
 381
 382   dash does not support arrays.
 383
 384 =back
 385
 386
 387 =head2 fish
 388
 389 =head3 Installation
 390
 391 Put this in $HOME/.config/fish/config.fish:
 392
 393   source (which env_parallel.fish)
 394
 395 E.g. by doing:
 396
 397   echo 'source (which env_parallel.fish)' \
 398     >> $HOME/.config/fish/config.fish
 399
 400 =head3 Supported use
 401
 402 B<--env> is supported to export only the variable, alias, function, or
 403 array with the given name. Multiple B<--env>s can be given.
 404
 405 B<--session> is supported.
 406
 407 =over 8
 408
 409 =item aliases
 410
 411   alias myecho 'echo aliases'
 412   env_parallel myecho ::: work
 413   env_parallel -S server myecho ::: work
 414   env_parallel --env myecho myecho ::: work
 415   env_parallel --env myecho -S server myecho ::: work
 416
 417 =item functions
 418
 419   function myfunc
 420     echo functions $argv
 421   end
 422   env_parallel myfunc ::: work
 423   env_parallel -S server myfunc ::: work
 424   env_parallel --env myfunc myfunc ::: work
 425   env_parallel --env myfunc -S server myfunc ::: work
 426
 427 =item variables
 428
 429   set myvar variables
 430   env_parallel echo '$myvar' ::: work
 431   env_parallel -S server echo '$myvar' ::: work
 432   env_parallel --env myvar echo '$myvar' ::: work
 433   env_parallel --env myvar -S server echo '$myvar' ::: work
 434
 435 =item arrays
 436
 437   set myarray arrays work, too
 438   env_parallel -k echo '$myarray[{}]' ::: 1 2 3
 439   env_parallel -k -S server echo '$myarray[{}]' ::: 1 2 3
 440   env_parallel -k --env myarray echo '$myarray[{}]' ::: 1 2 3
 441   env_parallel -k --env myarray -S server \
 442     echo '$myarray[{}]' ::: 1 2 3
 443
 444 =back
 445
 446
 447 =head2 ksh
 448
 449 =head3 Installation
 450
 451 Put this in $HOME/.kshrc:
 452
 453   source env_parallel.ksh
 454
 455 E.g. by doing:
 456
 457   echo 'source env_parallel.ksh' >> $HOME/.kshrc
 458
 459 =head3 Supported use
 460
 461 B<--env> is supported to export only the variable, alias, function, or
 462 array with the given name. Multiple B<--env>s can be given.
 463
 464 B<--session> is supported.
 465
 466 =over 8
 467
 468 =item aliases
 469
 470   alias myecho='echo aliases'
 471   env_parallel myecho ::: work
 472   env_parallel -S server myecho ::: work
 473   env_parallel --env myecho myecho ::: work
 474   env_parallel --env myecho -S server myecho ::: work
 475
 476   alias multiline='echo multiline
 477     echo aliases'
 478   env_parallel multiline ::: work
 479   env_parallel -S server multiline ::: work
 480   env_parallel --env multiline multiline ::: work
 481   env_parallel --env multiline -S server multiline ::: work
 482
 483 =item functions
 484
 485   myfunc() { echo functions $*; }
 486   env_parallel myfunc ::: work
 487   env_parallel -S server myfunc ::: work
 488   env_parallel --env myfunc myfunc ::: work
 489   env_parallel --env myfunc -S server myfunc ::: work
 490
 491 =item variables
 492
 493   myvar=variables
 494   env_parallel echo '$myvar' ::: work
 495   env_parallel -S server echo '$myvar' ::: work
 496   env_parallel --env myvar echo '$myvar' ::: work
 497   env_parallel --env myvar -S server echo '$myvar' ::: work
 498
 499 =item arrays
 500
 501   myarray=(arrays work, too)
 502   env_parallel -k echo '${myarray[{}]}' ::: 0 1 2
 503   env_parallel -k -S server echo '${myarray[{}]}' ::: 0 1 2
 504   env_parallel -k --env myarray echo '${myarray[{}]}' ::: 0 1 2
 505   env_parallel -k --env myarray -S server \
 506     echo '${myarray[{}]}' ::: 0 1 2
 507
 508 =back
 509
 510
 511 =head2 mksh
 512
 513 =head3 Installation
 514
 515 Put this in $HOME/.mkshrc:
 516
 517   source env_parallel.mksh
 518
 519 E.g. by doing:
 520
 521   echo 'source env_parallel.mksh' >> $HOME/.mkshrc
 522
 523 =head3 Supported use
 524
 525 B<--env> is supported to export only the variable, alias, function, or
 526 array with the given name. Multiple B<--env>s can be given.
 527
 528 B<--session> is supported.
 529
 530 =over 8
 531
 532 =item aliases
 533
 534   alias myecho='echo aliases'
 535   env_parallel myecho ::: work
 536   env_parallel -S server myecho ::: work
 537   env_parallel --env myecho myecho ::: work
 538   env_parallel --env myecho -S server myecho ::: work
 539
 540   alias multiline='echo multiline
 541     echo aliases'
 542   env_parallel multiline ::: work
 543   env_parallel -S server multiline ::: work
 544   env_parallel --env multiline multiline ::: work
 545   env_parallel --env multiline -S server multiline ::: work
 546
 547 =item functions
 548
 549   myfunc() { echo functions $*; }
 550   env_parallel myfunc ::: work
 551   env_parallel -S server myfunc ::: work
 552   env_parallel --env myfunc myfunc ::: work
 553   env_parallel --env myfunc -S server myfunc ::: work
 554
 555 =item variables
 556
 557   myvar=variables
 558   env_parallel echo '$myvar' ::: work
 559   env_parallel -S server echo '$myvar' ::: work
 560   env_parallel --env myvar echo '$myvar' ::: work
 561   env_parallel --env myvar -S server echo '$myvar' ::: work
 562
 563 =item arrays
 564
 565   myarray=(arrays work, too)
 566   env_parallel -k echo '${myarray[{}]}' ::: 0 1 2
 567   env_parallel -k -S server echo '${myarray[{}]}' ::: 0 1 2
 568   env_parallel -k --env myarray echo '${myarray[{}]}' ::: 0 1 2
 569   env_parallel -k --env myarray -S server \
 570     echo '${myarray[{}]}' ::: 0 1 2
 571
 572 =back
 573
 574
 575 =head2 pdksh
 576
 577 =head3 Installation
 578
 579 Put this in $HOME/.profile:
 580
 581   source env_parallel.pdksh
 582
 583 E.g. by doing:
 584
 585   echo 'source env_parallel.pdksh' >> $HOME/.profile
 586
 587 =head3 Supported use
 588
 589 B<--env> is supported to export only the variable, alias, function, or
 590 array with the given name. Multiple B<--env>s can be given.
 591
 592 B<--session> is supported.
 593
 594 =over 8
 595
 596 =item aliases
 597
 598   alias myecho="echo aliases";
 599   env_parallel myecho ::: work;
 600   env_parallel -S server myecho ::: work;
 601   env_parallel --env myecho myecho ::: work;
 602   env_parallel --env myecho -S server myecho ::: work
 603
 604 =item functions
 605
 606   myfunc() { echo functions $*; };
 607   env_parallel myfunc ::: work;
 608   env_parallel -S server myfunc ::: work;
 609   env_parallel --env myfunc myfunc ::: work;
 610   env_parallel --env myfunc -S server myfunc ::: work
 611
 612 =item variables
 613
 614   myvar=variables;
 615   env_parallel echo "\$myvar" ::: work;
 616   env_parallel -S server echo "\$myvar" ::: work;
 617   env_parallel --env myvar echo "\$myvar" ::: work;
 618   env_parallel --env myvar -S server echo "\$myvar" ::: work
 619
 620 =item arrays
 621
 622   myarray=(arrays work, too);
 623   env_parallel -k echo "\${myarray[{}]}" ::: 0 1 2;
 624   env_parallel -k -S server echo "\${myarray[{}]}" ::: 0 1 2;
 625   env_parallel -k --env myarray echo "\${myarray[{}]}" ::: 0 1 2;
 626   env_parallel -k --env myarray -S server \
 627     echo "\${myarray[{}]}" ::: 0 1 2
 628
 629 =back
 630
 631
 632 =head2 sh
 633
 634 =head3 Installation
 635
 636 Put this in $HOME/.profile:
 637
 638   . env_parallel.sh
 639
 640 E.g. by doing:
 641
 642   echo '. env_parallel.sh' >> $HOME/.profile
 643
 644 =head3 Supported use
 645
 646 B<--env> is supported to export only the variable, or alias with the
 647 given name. Multiple B<--env>s can be given.
 648
 649 B<--session> is supported.
 650
 651 =over 8
 652
 653 =item aliases
 654
 655   sh does not support aliases.
 656
 657 =item functions
 658
 659   myfunc() { echo functions $*; }
 660   env_parallel myfunc ::: work
 661   env_parallel -S server myfunc ::: work
 662   env_parallel --env myfunc myfunc ::: work
 663   env_parallel --env myfunc -S server myfunc ::: work
 664
 665 =item variables
 666
 667   myvar=variables
 668   env_parallel echo '$myvar' ::: work
 669   env_parallel -S server echo '$myvar' ::: work
 670   env_parallel --env myvar echo '$myvar' ::: work
 671   env_parallel --env myvar -S server echo '$myvar' ::: work
 672
 673 =item arrays
 674
 675   sh does not support arrays.
 676
 677 =back
 678
 679
 680 =head2 tcsh
 681
 682 B<env_parallel> for B<tcsh> breaks B<$PARALLEL>, so do not use
 683 B<$PARALLEL>.
 684
 685 =head3 Installation
 686
 687 Put this in $HOME/.tcshrc:
 688
 689   source `which env_parallel.tcsh`
 690
 691 E.g. by doing:
 692
 693   echo 'source `which env_parallel.tcsh`' >> $HOME/.tcshrc
 694
 695 =head3 Supported use
 696
 697 B<--env> is supported to export only the variable, alias, or
 698 array with the given name. Multiple B<--env>s can be given.
 699
 700 =over 8
 701
 702 =item aliases
 703
 704   alias myecho 'echo aliases'
 705   env_parallel myecho ::: work
 706   env_parallel -S server myecho ::: work
 707   env_parallel --env myecho myecho ::: work
 708   env_parallel --env myecho -S server myecho ::: work
 709
 710 =item functions
 711
 712 Not supported by B<tcsh>.
 713
 714 =item variables
 715
 716   set myvar=variables
 717   env_parallel echo '$myvar' ::: work
 718   env_parallel -S server echo '$myvar' ::: work
 719   env_parallel --env myvar echo '$myvar' ::: work
 720   env_parallel --env myvar -S server echo '$myvar' ::: work
 721
 722 =item arrays with no special chars
 723
 724   set myarray=(arrays work, too)
 725   env_parallel -k echo \$'{myarray[{}]}' ::: 1 2 3
 726   env_parallel -k -S server echo \$'{myarray[{}]}' ::: 1 2 3
 727   env_parallel -k --env myarray echo \$'{myarray[{}]}' ::: 1 2 3
 728   env_parallel -k --env myarray -S server \
 729     echo \$'{myarray[{}]}' ::: 1 2 3
 730
 731 =back
 732
 733
 734 =head2 Zsh
 735
 736 =head3 Installation
 737
 738 Put this in $HOME/.zshrc:
 739
 740   . env_parallel.zsh
 741
 742 E.g. by doing:
 743
 744   echo '. env_parallel.zsh' >> $HOME/.zshenv
 745
 746 =head3 Supported use
 747
 748 B<--env> is supported to export only the variable, alias, function, or
 749 array with the given name. Multiple B<--env>s can be given.
 750
 751 B<--session> is supported.
 752
 753 =over 8
 754
 755 =item aliases
 756
 757   alias myecho='echo aliases'
 758   env_parallel myecho ::: work
 759   env_parallel -S server myecho ::: work
 760   env_parallel --env myecho myecho ::: work
 761   env_parallel --env myecho -S server myecho ::: work
 762
 763   alias multiline='echo multiline
 764     echo aliases'
 765   env_parallel multiline ::: work
 766   env_parallel -S server multiline ::: work
 767   env_parallel --env multiline multiline ::: work
 768   env_parallel --env multiline -S server multiline ::: work
 769
 770 =item functions
 771
 772   myfunc() { echo functions $*; }
 773   env_parallel myfunc ::: work
 774   env_parallel -S server myfunc ::: work
 775   env_parallel --env myfunc myfunc ::: work
 776   env_parallel --env myfunc -S server myfunc ::: work
 777
 778 =item variables
 779
 780   myvar=variables
 781   env_parallel echo '$myvar' ::: work
 782   env_parallel -S server echo '$myvar' ::: work
 783   env_parallel --env myvar echo '$myvar' ::: work
 784   env_parallel --env myvar -S server echo '$myvar' ::: work
 785
 786 =item arrays
 787
 788   myarray=(arrays work, too)
 789   env_parallel -k echo '${myarray[{}]}' ::: 1 2 3
 790   env_parallel -k -S server echo '${myarray[{}]}' ::: 1 2 3
 791   env_parallel -k --env myarray echo '${myarray[{}]}' ::: 1 2 3
 792   env_parallel -k --env myarray -S server \
 793     echo '${myarray[{}]}' ::: 1 2 3
 794
 795 =back
 796
 797
 798 =head1 EXIT STATUS
 799
 800 Same as GNU B<parallel>.
 801
 802
 803 =head1 AUTHOR
 804
 805 When using GNU B<env_parallel> for a publication please cite:
 806
 807 O. Tange (2018): GNU Parallel 2018, March 2018, ISBN 9781387509881,
 808 DOI: 10.5281/zenodo.1146014.
 809
 810 This helps funding further development; and it won't cost you a cent.
 811 If you pay 10000 EUR you should feel free to use GNU Parallel without citing.
 812
 813 Copyright (C) 2007-10-18 Ole Tange, http://ole.tange.dk
 814
 815 Copyright (C) 2008-2010 Ole Tange, http://ole.tange.dk
 816
 817 Copyright (C) 2010-2024 Ole Tange, http://ole.tange.dk and Free
 818 Software Foundation, Inc.
 819
 820
 821 =head1 LICENSE
 822
 823 This program is free software; you can redistribute it and/or modify
 824 it under the terms of the GNU General Public License as published by
 825 the Free Software Foundation; either version 3 of the License, or
 826 at your option any later version.
 827
 828 This program is distributed in the hope that it will be useful,
 829 but WITHOUT ANY WARRANTY; without even the implied warranty of
 830 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 831 GNU General Public License for more details.
 832
 833 You should have received a copy of the GNU General Public License
 834 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 835
 836 =head2 Documentation license I
 837
 838 Permission is granted to copy, distribute and/or modify this
 839 documentation under the terms of the GNU Free Documentation License,
 840 Version 1.3 or any later version published by the Free Software
 841 Foundation; with no Invariant Sections, with no Front-Cover Texts, and
 842 with no Back-Cover Texts.  A copy of the license is included in the
 843 file LICENSES/GFDL-1.3-or-later.txt.
 844
 845
 846 =head2 Documentation license II
 847
 848 You are free:
 849
 850 =over 9
 851
 852 =item B<to Share>
 853
 854 to copy, distribute and transmit the work
 855
 856 =item B<to Remix>
 857
 858 to adapt the work
 859
 860 =back
 861
 862 Under the following conditions:
 863
 864 =over 9
 865
 866 =item B<Attribution>
 867
 868 You must attribute the work in the manner specified by the author or
 869 licensor (but not in any way that suggests that they endorse you or
 870 your use of the work).
 871
 872 =item B<Share Alike>
 873
 874 If you alter, transform, or build upon this work, you may distribute
 875 the resulting work only under the same, similar or a compatible
 876 license.
 877
 878 =back
 879
 880 With the understanding that:
 881
 882 =over 9
 883
 884 =item B<Waiver>
 885
 886 Any of the above conditions can be waived if you get permission from
 887 the copyright holder.
 888
 889 =item B<Public Domain>
 890
 891 Where the work or any of its elements is in the public domain under
 892 applicable law, that status is in no way affected by the license.
 893
 894 =item B<Other Rights>
 895
 896 In no way are any of the following rights affected by the license:
 897
 898 =over 2
 899
 900 =item *
 901
 902 Your fair dealing or fair use rights, or other applicable
 903 copyright exceptions and limitations;
 904
 905 =item *
 906
 907 The author's moral rights;
 908
 909 =item *
 910
 911 Rights other persons may have either in the work itself or in
 912 how the work is used, such as publicity or privacy rights.
 913
 914 =back
 915
 916 =back
 917
 918 =over 9
 919
 920 =item B<Notice>
 921
 922 For any reuse or distribution, you must make clear to others the
 923 license terms of this work.
 924
 925 =back
 926
 927 A copy of the full license is included in the file as
 928 LICENCES/CC-BY-SA-4.0.txt
 929
 930
 931 =head1 DEPENDENCIES
 932
 933 B<env_parallel> uses GNU B<parallel>.
 934
 935
 936 =head1 SEE ALSO
 937
 938 B<parallel>(1), B<ash>(1), B<bash>(1), B<csh>(1), B<dash>(1),
 939 B<fish>(1), B<ksh>(1), B<pdksh>(1) B<tcsh>(1), B<zsh>(1).
 940
 941
 942 =cut