Unified · Split
| @@ -301,6 +301,29 @@ The operator is invoked and its value substituted. · 300 unmodified lines | ||
| 301 | 301 | See |
| 302 | 302 | .IR "Built-in Commands" , |
| 303 | 303 | below, for more information on builtins. |
| 304 | +.HP | |
| 305 | +.BI <{ command } | |
| 306 | +.HP | |
| 307 | +.BI >{ command } | |
| 308 | +.br | |
| 309 | +The | |
| 310 | +.I command | |
| 311 | +is executed asynchronously with its standard output or standard input | |
| 312 | +connected to a pipe. | |
| 313 | +The value of the argument is the name of a file | |
| 314 | +referring to the other end of the pipe. | |
| 315 | +This allows the construction of | |
| 316 | +non-linear pipelines. | |
| 317 | +For example, the following runs two commands | |
| 318 | +.B old | |
| 319 | +and | |
| 320 | +.B new | |
| 321 | +and uses | |
| 322 | +.B cmp | |
| 323 | +to compare their outputs | |
| 324 | +.EX | |
| 325 | + cmp <{old} <{new} | |
| 326 | +.EE | |
| 304 | 327 | .PD |
| 305 | 328 | .SS Free Carets |
| 306 | 329 | In most circumstances, |
| @@ -394,6 +417,12 @@ may be redirected from a file by the sequence · 87 unmodified lines | ||
| 394 | 417 | or by the sequence |
| 395 | 418 | .BI <> file \f1, |
| 396 | 419 | which opens the file for writing as well as reading. |
| 420 | +Note that if | |
| 421 | +.I file | |
| 422 | +is in fact a parsed braced block, the redirection will be treated as | |
| 423 | +pipe to the given command - it is identical to the | |
| 424 | +.B "<{}" | |
| 425 | +operator mentioned above. | |
| 397 | 426 | .PP |
| 398 | 427 | Redirections may be applied to a file-descriptor other than standard input |
| 399 | 428 | or output by qualifying the redirection operator |
| @@ -463,17 +463,10 @@ its standard input is connected; otherwise file descriptor · 462 unmodified lines | ||
| 463 | 463 | is connected. |
| 464 | 464 | .B Pipe |
| 465 | 465 | yields the name of a file that can be opened to access |
| 466 | −the other end of the pipe. This allows the construction | |
| 467 | −of non-linear pipelines. For example, the following runs two commands | |
| 468 | −.B old | |
| 469 | −and | |
| 470 | −.B new | |
| 471 | −and uses | |
| 472 | −.B cmp | |
| 473 | −to compare their outputs | |
| 474 | −.EX | |
| 475 | − cmp ${pipe from {old}} ${pipe from {new}} | |
| 476 | −.EE | |
| 466 | +the other end of the pipe. Note that this command is now | |
| 467 | +deprecated in favour of the | |
| 468 | +.B <{} | |
| 469 | +redirection operator built in to the shell. | |
| 477 | 470 | .TP |
| 478 | 471 | .B ${split} |
| 479 | 472 | .B Split |