-r /REGEXP/, --regex=/REGEXP/ or --regex=@regexfile Make a tag for each line matching pattern REGEXP in the following files. regexfile is a file containing one REGEXP per line. REGEXP is anchored (as if preceded by ^). The form /REGEXP/NAME/ creates a named tag. For example Tcl named tags can be created with: --regex=/proc[ \t]+\([^ \t]+\)/\1/.