You probably already know how to select text (Section 5.13) in an xterm, and you've probably discovered that double-clicking Section 5.13 will select the entire word around the pointer. What you may not know is that it is possible to change what defines a "word."
xterm maintains a table of all the
ASCII characters and their
character classes. Any sequence of adjacent characters
of the same class is treated as a word.
Numbers, letters, and the underscore are in class 48
(which is the ASCII code for the character 0) and
SPACE and
TAB are in class 32 (the ASCII code for SPACE). By default,
all the other characters are in classes by themselves.
For Unix users, this isn't the most useful default; it would be better if you could select filenames, email addresses, URLs, resource specifications, etc. as single words even though they often contain punctuation characters.
You can modify the character class table with xterm's
charClass
resource variable (Section 6.3). The value this resource
accepts is a comma-separated list; each item on the list is an
ASCII character code or range of characters, followed by
a colon, followed by the character class to which the character should be added.
I set the charClass resource as
follows:
xterm*charClass: 33:48, 37:48, 42:48, 45-47:48, 63-64:48, 126:48
This tells xterm to treat !, %, *, -, ., /,
?, @, and ~ as characters of the same class as numbers and letters. You may also
want to treat : as a member of this class, for URLs; in that case, use the
following charClass string:
xterm*charClass: 33:48, 37:48, 42:48, 45-47:48, 58:48, 63-64:48, 126:48
—DJF and SJC