| Form | Meaning |
| cmd & | Execute cmd in background |
| cmd1; cmd2 | Execute multiple cmds |
| { cmd1; cmd2; } | Execute commands as a group in the current shell |
| (cmd1; cmd2) | Execute commands as a group in a subshell |
| cmd1 │ cmd2 | use output from cmd1 as input to cmd2 |
| cmd1 `cmd2` | use cmd2 output as arguments to cmd1 |
| cmd $((expression)) | Use the result of expression as argument to cmd |
| cmd1 && cmd2 | execute cmd1 and then (if cmd1 succeeds)cmd2 |
| cmd1 ││ cmd2 | execute either cmd1 or (if cmd1 fails)cmd2 |
| !cmd | execute cmd, and produce a zero exit status if cmd exits with a nonzero status. produce a nonzero status when
cmd exits with a zero status |