Managing remote ELinks instances

Some programs provide the ability to pass URIs to external programs. When stumbling upon a reference to a page you want to see, it is sometimes a kludge to copy and paste it into ELinks. This is where -remote can be a nifty solution.

When invoking ELinks with the -remote argument, it does not start a new instance, but instead connects to an already running ELinks, making it possible to control that ELinks instance. The -remote command line switch takes a command consisting of the action to invoke and any parameters to the action. Commands must begin with a nonempty sequence of ASCII alphabetic characters followed by optional whitespace and an opening parenthesis. They must end with a closing parenthesis optionally followed by whitespace. Here is an example for opening freshmeat.net in a new tab:

$ elinks -remote "openURL(http://freshmeat.net/, new-tab)"

When running this command in a terminal, you will see a small delay before ELinks returns. If no running instance was found, it will return with the error message:

ELinks: No remote session to connect to.

All URLs passed to the openURL() commands can be URL prefixes, so the command above could have simply used “openURL(fm, new-tab)”.

Limitations and outstanding issues

Remote control is implemented using the intercommunication socket created in ~/.config/elinks/, so the command has to be run on the same machine as the instance you want to control; or put differently: the two ELinkses need to share a file system that supports socket files, which rules out usage of -remote over NFS. This also implies that the ELinks instance you want to control should be started without passing -no-home nor -no-connect.

The built-in -remote support is to some degree compatible with the one Mozilla provides (http://www.mozilla.org/unix/remote.html), but with some homebrew extensions added and few unsupported features. All the supported actions are documented below.

Under some circumstances, use of the -remote control can cause ELinks to become unresponsive. This is cause by the current key press and mouse focus being redirected to new tabs or dialogs opened by the -remote action.

Remote Actions

The command syntax is case-insensitive. For readability, we use the casing in the listing of supported commands.

Table 1. Mozilla -remote compatible commands.

Command Description
ping() Checks for existence of a remote instance. Makes it possible for scripts to query if remote controlling is possible.
openURL() Prompts for a URL in current tab by opening the Goto dialog.
openURL(URL) Open the passed URL in current tab.
openURL(URL, new-tab) Opens the passed URL in new tab.
openURL(URL, new-window) Opens the passed URL in new window.
xfeDoCommand(openBrowser) Opens an ELinks instance in a new window. This ELinks instance will connect to the already running one.

Table 2. ELinks extensions.

Command Description
addBookmark(URL, title) Bookmarks the passed URL and set title.
infoBox(text) Show text in a message box.
reload() Reload the document in the current tab.
search(string) Search for the string in the current tab

-remote can also take a list of URLs without an explicit action, in which case the URL arguments will be opened in new tabs in the remote instance. For example, by running:

$ elinks -remote slashdot.org fm g:elinks

new tabs containing slashdot.org, freshmeat.net and a Google search of elinks will be opened.