Mac OS X for Unix Geeks

Customizing the Terminal on the Fly

You can customize the Terminal in shell scripts using escape sequences or AppleScript commands. xterm users may be familiar with using the following to set the xterm’s title:

echo '^[]2;My-Window-Title^G'

Mac OS X’s Terminal accepts this sequence as well.

Tip

^[ is the ASCII ESC character, and ^G is the ASCII BEL character. (The BEL character is used to ring the terminal bell, but in this context, it terminates an escape sequence.) The escape sequences described here are ANSI escape sequences, which differ from the shell escape sequences described earlier. ANSI escape sequences are used to manipulate a Terminal window (such as by moving the cursor or setting the title). Shell escape sequences are used to tell the shell to treat a metacharacter, such as |, as a literal character rather than an instruction to pipe standard output somewhere else.

To type the ^[ characters in tcsh, use the key sequence Control-V Escape (press Control-V and release, then press the Escape key). To type ^G, use Control-V Control-G. The vi editor supports the same key sequence; Emacs uses Control-Q instead of Control-V.

You can capture this escape sequence in a shell alias:

alias settitle 'echo -n "^[]2;\!*^G"'

Then you can change the title by issuing this command:

settitle your fancy title here

You may want to package this as a shell script and make it available to everyone who uses your system, as shown in Example 1-3.

Example 1-3. Setting the Terminal title in a shell script ...