| 329 | |
| 330 | === Pipe ( | ) === |
| 331 | |
| 332 | The pipe command, '''|''', takes the output of one command and passes it to another. For example we could "pipe" the output of '''cat''' to '''grep''' in order to search a file for a particular string |
| 333 | |
| 334 | {{{ |
| 335 | [tulaneID@cypress1 examples]$ cat numbers.txt | grep 1 |
| 336 | 01 |
| 337 | 10 |
| 338 | [tulaneID@cypress1 examples]$ |
| 339 | }}} |
| 340 | |
| 341 | === history === |
| 342 | Displays the command history list with line numbers. You can add an optional integer, n, argument to display only the last n commands |
| 343 | |
| 344 | {{{ |
| 345 | [tulaneID@cypress1 examples]$ history 2 |
| 346 | 299 cat numbers.txt | grep 1 |
| 347 | 300 history 2 |
| 348 | [tulaneID@cypress1 examples]$ |
| 349 | }}} |
| 350 | |
| 351 | Note: '''history''', '''|''', and '''grep''' when used together are a powerful combination as they allow you to search for old commands that you may not remember the exact syntax for: |
| 352 | |
| 353 | {{{ |
| 354 | [tulaneID@cypress1 examples]$ history | grep chmod |
| 355 | 153 chmod u+x myscript.sh |
| 356 | 204 chmod +x myexecutable.sh |
| 357 | 271 chmod +x myscript.sh |
| 358 | 273 chmod -x myscript.sh |
| 359 | 301 history | grep chmod |
| 360 | [tulaneID@cypress1 examples]$ |
| 361 | }}} |
| 362 | |