Using csh & tcsh

Event Modifiers

Following a word designator (or an event specifier if there is no designator) you can add an event modifier:

!event:words:modifiers
!event:modifiers

Modifiers change the way an event is treated. If you add :p to an event reference, the event is printed (echoed) but not executed. Other modifiers change the text of the recalled event or words in some way. For instance, adding :s/a/b changes a to b in the command line. This feature is useful for fixing mistakes or modifying an argument. Possible modifiers are listed in Table 6-5.

Table 6-5. History Reference Modifiers

Modifier	Description
p	Print resulting command without executing it
s/old/new/	Perform substitution, replacing old with new
&	Repeat previous s substitution
r	Root of filename (everything but extension following dot)
e	Extension of filename (suffix following dot)
h	Head of pathname (all but last component)
t	Tail of pathname (last component)
q	Quote words (prevents filename pattern expansion)
x	Like q but break into words at whitespace
u	Make first lowercase letter uppercase (tcsh only)
l	Make first uppercase letter lowercase (tcsh only)
g	Apply modifier following g globally to each word
a	Apply modifier(s) following a as many times as possible to a word. If used with g, a is applied to all words. (tcsh only)

Modifiers vary a great deal in terms of their general usefulness. I find that :s and :p are the most valuable. The following sections discuss :p, the substitution modifier :s (along with the repetition modifiers :g, :a, and :&