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 ~/.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) Bookmarks the passed URL.
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.