Mac OS X Tiger in a Nutshell: A Desktop Quick Reference (In a Nutshell (OReilly))
Table 4-1 is a sampling of features that are common to bash and other Unix shells .
Table 4-1. Common shell features
| Symbol/command | Meaning/action |
|---|---|
| > | Redirect output |
| >> | Append to file |
| < | Redirect input |
| << | Here document (redirect input) |
|
| Pipe output |
| & | Run process in background |
| ; | Separate commands on same line |
| * | Match any character(s) in filename |
| ? | Match single character in filename |
| ! n | Repeat command number n |
| [ ] | Match any characters enclosed |
| ( ) | Execute in subshell |
| '' | Substitute output of enclosed command |
| " " | Partial quote (allows variable and command expansion) |
| ' ' | Full quote (no expansion) |
| \ | Quote following character |
| $ var | Use value for variable |
| $$ | Process ID |
| $0 | Command name |
| $ n | n th argument (0< n |
| $* | All arguments as simple words |
| # | Begin comment |
| Tab | Complete current word |
| bg | Background execution |
| break | Break from loop statements |
| cd | Change directory |
| continue | Resume a program loop |
| echo | Display output |
| eval | Evaluate arguments |
| exec | Execute a new shell |
| fg | Foreground execution |
| jobs | Show active jobs |
| kill | Terminate running jobs |
| newgrp | Change to a new group |
| shift | Shift positional parameters |
| stop | Suspend a background job |
| suspend | Suspend a foreground job (such as a shell created by su ) |
| time | Time a command |
| umask | Set default file permissions for new files |
| unset | Erase variable or function definitions |
| wait | Wait for a background job to finish |