Frequently Used Commands
Shell programming involves a mixture of built-in shell commands and standard programs that run in all shells. While most shells offer the same basic set of commands, there are often variations in the syntax and behavior of those commands. In addition to the shell commands, Mac OS X also provides a set of standard programs that run in all shells.
Table A-4 lists some of the more commonly used commands and programs. Because most of the items in this table are not built-in shell commands, you can use them from any shell. For syntax and usage information for each command, see the corresponding man page. For a more in-depth list of commands and their accompanying documentation, see Mac OS X Man Pages.
Table A-4 Frequently used commands and programsCommand | Meaning | Description |
|---|
cat
| Catenate | Catenates the specified list of files to stdout. |
cd
| Change Directory | A common shell command used to navigate the directory hierarchy. |
cp
| Copy | Copies files and directories (using the -r option) from one location to another. |
date
| Date | Displays the current date and time using the standard format. You can display this information in other formats by invoking the command with specific arguments. |
echo
| Echo to Output | Writes its arguments to stdout. This command is most often used in shell scripts to print status information to the user. |
less
| Scroll Through Text | Used to scroll through the contents of a file or the results of another shell command. This command allows forward and backward navigation through the text. |
ls
| List | Displays the contents of the current directory. Specify the -a argument to list all directory contents (including hidden files and directories). Use the -l argument to display detailed information for each entry. |
mkdir
| Make Directory | Creates a new directory. |
more
| Scroll Through Text | Similar to the less command but more restrictive. Allows forward scrolling through the contents of a file or the results of another shell command. |
mv
| Move | Moves files and directories from one place to another. You also use this command to rename files and directories. |
open
| Open an application or file. | You can use this command to launch applications from Terminal and optionally open files in that application. |
pwd
| Print Working Directory | Displays the full path of the current directory. |
rm
| Remove | Deletes the specified file or files. You can use pattern matching characters (such as the asterisk) to match more than one file. You can also remove directories with this command, although use of rmdir is preferred. |
rmdir
| Remove Directory | Deletes a directory. The directory must be empty before you delete it. |
Ctrl-C | Abort | Sends an abort signal to the current command. In most cases this causes the command to terminate, although commands may install signal handlers to trap this command and respond differently. |
