Using the tcsh Shell (Mac OS X for Unix Geeks)

Last login: Fri Jul 19 19:24:52 on ttyp1 Welcome to Darwin! Running .tcshrc script Running .login script [Brian-Jepsons-Computer:~] bjepson% tcsh Running .tcshrc script [Brian-Jepsons-Computer:~] bjepson% exit exit [Brian-Jepsons-Computer:~] bjepson% exit logout Running .logout script

1.5.3. Command-Line Editing with tcsh

Mac OS X's default shell, tcsh, lets you move your cursor around in the command line, editing the line as you type. There are two main modes for editing the command line, based on the two most commonly used text editors, Emacs and vi . Emacs mode is the default; you can switch between the modes with the following commands:

bindkey -e      Select Emacs bindings
bindkey -v      Select vi bindings

The main difference between the Emacs and vi bindings is that the Emacs bindings are modeless (i.e., they always work). With the vi bindings, you must switch between insert and command modes; different commands are useful in each mode. Additionally:

Emacs mode is simpler; vi mode allows finer control.
Emacs mode allows you to yank cut text and set a mark; vi mode does not.
The command-history-searching capabilities of the two modes differ.

1.5.3.1. Emacs mode

Table 1-2, Table 1-3, and Table 1-4 describe the various editing keystrokes available in Emacs mode.

Table 1-2. Cursor positioning commands (Emacs mode)

Command	Description
Control-B	Moves the cursor back (left) one character.
Control-F	Moves the cursor forward (right) one character.
Esc then B	Moves the cursor back one word.
Esc then F	Moves the cursor forward one word.
Control-A	Moves the cursor to the beginning of the line.
Control-E	Moves the cursor to the end of the line.

Table 1-3. Text deletion commands (Emacs mode)

Command	Description
Del or Control-H	Deletes the character to the left of the cursor.
Control-D	Deletes the character under the cursor.
Esc then D	Deletes the next word.
Esc then Delete or Esc then Control-H	Deletes the previous word.
Control-K	Deletes from the cursor to the end of the line.
Control-U	Deletes the entire line.
Control-W	Deletes everything to the left of the cursor.
Control-Y	Yanks the previously deleted string.

Table 1-4. Command control (Emacs mode)

Command	Description
Control-P	Recalls the previous command from history.
Control-N	Recalls the next command from history.
Up arrow	Recalls the previous command from history.
Down arrow	Recalls the next command from history.
File-fragment Tab	Performs command-line completion. file-fragment can be a filename, a directory, or an executable in your $PATH.
cmd-fragment Esc then P	Searches history for cmd-fragment, which must be the beginning of a command.
cmd-fragment Esc then N	Like Esc then P, but searches forward in the history.
Esc num	Repeats the next command num times.

1.5.3.2. vi mode

vi mode has two submodes, insert and command mode. The default mode is insert. You can toggle between the modes by pressing Esc. Alternatively, in command mode, typing a (append) or i (insert) will return you to insert mode.

Table 1-5 through Table 1-11 describe the editing keystrokes available in vi mode.

Table 1-5. Commands available (vi's insert and command mode)

Command	Description
Control-P	Recalls the previous command from history.
Control-N	Recalls the next command from history.
Up arrow	Recalls the previous command from history.
Down arrow	Recalls the next command from history.

Table 1-6. Editing commands (vi insert mode)

Command	Description
Control-B	Moves the cursor back (left) one character.
Control-F	Moves the cursor forward (right) one character.
Control-A	Moves the cursor to the beginning of the line.
Control-E	Moves the cursor to the end of the line.
Delete or Control-H	Deletes the character to the left of the cursor.
Control-W	Deletes the previous word.
Control-U	Deletes from the beginning of the line to the cursor.
Control-K	Deletes from the cursor to the end of the line.

Table 1-7. Cursor positioning commands (vi command mode)

Command	Description
h or Control-H	Moves the cursor back (left) one character.
l or Space	Moves the cursor forward (right) one word.
w	Moves the cursor forward (right) one word.
b	Moves the cursor back (left) one word.
e	Moves the cursor to the end of the next word.
W, B, E	Has the same effect as w, b, and e, but treats whitespace as a word separator instead of any non-alphanumeric character.
^ or Control-A	Moves the cursor to the beginning of the line (first non-whitespace character).
O	Moves the cursor to the beginning of the line.
$ or Control-E	Moves the cursor to the end of the line.

Table 1-8. Text insertion commands (vi command mode)

Command	Description
a	Appends new text after the cursor until Esc is pressed.
i	Inserts new text before the cursor until Esc is pressed.
A	Appends new text after the end of the line until Esc is pressed.
I	Inserts new text before the beginning of the line until Esc is pressed.

Table 1-9. Text deletion commands (vi command mode)

Command	Description
x	Deletes the character under the cursor.
X or Delete	Deletes the character to the left of the cursor.
dm	Deletes from the cursor to the end of motion command m.
D	Deletes from the cursor to the end of the line (similar to issuing `d$`).
Control-W	Deletes the previous word.
Control-U	Deletes from the beginning of the line up to the cursor.
Control-K	Deletes from the cursor to the end of the line.

Table 1-10. Text replacement commands (vi command mode)

Command	Description
cm	Changes the characters from the cursor to the end of motion command m until Esc is pressed.
C	Has the same effect as `c$`.
rc	Replaces the character under the cursor with the character c.
R	Replaces multiple characters until Esc is pressed.
s	Substitutes the character under the cursor with the characters typed until Esc is pressed.

Table 1-11. Character-seeking motion commands (vi command mode)

Command	Description
fc	Moves the cursor to the next instance of c in the line.
Fc	Moves the cursor to the previous instance of c in the line.
tc	Moves the cursor just after the next instance of c in the line.
Tc	Moves the cursor just after the previous instance of c in the line.
;	Repeats the previous f or F command.
,	Repeats the previous f or F command in the opposite direction.

1.5.3.3. Additional command-line keys

As we've just illustrated, the tcsh shell offers dozens of special keystroke characters for navigation on the command line. Table 1-12 lists some additional command-line keys for use in either Emacs or vi editing mode.

Table 1-12. Additional key commands for the tcsh shell

Key command	Description
Control-C	Interrupts the process; cancels the previous command (-. works as well).
Control-D	Signals end-of-input for some programs and returns you to the shell prompt. If Control-D is issued at a shell prompt, it will terminate the shell session and close the Terminal window, if you've set your Terminal preferences to close the window when the shell exits.
Control-J	Has the same effect as pressing the Return (or Enter) key. Hitting Control-J after issuing a command will invoke the command, or it will take you to the next line in the shell if no command was given.
Control-K	Removes everything to the right of the insertion point.
Control-L	Clears the display.
Control-Q	Restarts the output after a pause by Control-S.
Control-S	Pauses the output from a program that's writing to the screen.
Control-T	Transposes the previous two characters.
Control-Z	Suspends a process. To restart the process, issue the bg or fg command to place the process in the background or foreground, respectively.
Esc then C	Capitalizes the word following the insertion point.
Esc then Esc	Completes the name if only a partial pathname or filename is entered.
Esc then L	Changes the next word to all lowercase letters.
Esc then U	Changes the next word to all uppercase letters.
Tab	Has the same effect as pressing the Esc key twice.

1.5. Using the tcsh Shell

1.5.1. Customizing the tcsh Shell

1.5.2. Working with File and Directory Names

1.5.2.1. Tab completion