File links can contain additional information to make Emacs jump to a particular location in the file when following a link. This can be a line number or a search option after a double1 colon. For example, when the command C-c l creates a link (see Handling links) to a file, it encodes the words in the current line as a search string that can be used to find this line back later when following the link with C-c C-o.
Here is the syntax of the different ways to attach a search to a file link, together with an explanation:
[[file:~/code/main.c::255]]
[[file:~/xx.org::My Target]]
[[file:~/xx.org::*My Target]]
[[file:~/xx.org::#my-custom-id]]
[[file:~/xx.org::/regexp/]]
255My Target*My Target#my-custom-idCUSTOM_ID
property/regexp/regexp.
This uses the Emacs command occur to list all
matches in a separate window. If the target file is in
Org-mode, org-occur is used to create a sparse
tree with the matches.
As a degenerate case, a file link with an empty file name can
be used to search the current file. For example,
[[file:::find me]] does a search for
‘find me’ in
the current file, just as ‘[[find
me]]’ would.