32.1.3 Modifiers

After the optional word designator, you can add a sequence of one or more of the following modifiers, each preceded by a :.

h
Remove a trailing pathname component, leaving only the head.
t
Remove all leading pathname components, leaving the tail.
r
Remove a trailing suffix of the form .suffix, leaving the basename.
e
Remove all but the trailing suffix.
p
Print the new command but do not execute it.
s/old/new/
Substitute new for the first occurrence of old in the event line. Any delimiter may be used in place of /. The delimiter may be quoted in old and new with a single backslash. If & appears in new, it is replaced by old. A single backslash will quote the &. The final delimiter is optional if it is the last character on the input line.
&
Repeat the previous substitution.
g
a
Cause changes to be applied over the entire event line. Used in conjunction with s, as in gs/old/new/, or with &.
G
Apply the following s modifier once to each word in the event.