Running Other Programs

Epsilon provides several methods for running other programs from within Epsilon. The push command on Ctrl-x Ctrl-e starts a command processor (shell) running. You can then issue shell commands. When you type the "exit" command, you will return to Epsilon and can resume your work right where you left off.

With a numeric argument, the command asks for a command line to pass to the shell, runs this command, then returns.

While Epsilon runs a command processor or other program with the push command, it looks like you ran the program from outside of Epsilon. But Epsilon can make a copy of the input and output that occurs during the program's execution, and show it to you when the program returns to Epsilon. If you set the variable capture-output to a nonzero value (normally it has the value zero), Epsilon will make such a transcript. When you return to Epsilon, this transcript will appear in a buffer named "process".

You can use the filter-region command on Alt-| to process the current region through an external command. Epsilon will run the command, sending a copy of the region to it as its standard input. By default, the external command's output goes to a new buffer named "filter-output", but with a negative prefix argument the command asks for the buffer name to use for output. Run filter-region with a non-negative numeric argument if you want the output to replace the current region.

The command shell-command is similar, but it doesn't send the current region as the command's input. It prompts for the name of an external program to run and displays the result in a buffer; with a non-negative numeric argument it inserts the command's output into the current buffer and with a negative prefix argument it prompts for the buffer to receive the output.

Configuration variables (see Configuration Variables) let you customize what command Epsilon runs when it wants to start a process. Epsilon runs the command file named by the EPSCOMSPEC configuration variable. If no such variable exists, Epsilon uses the standard COMSPEC environment variable instead. Epsilon reports an error if neither exists.

If a configuration variable named INTERSHELLFLAGS has been defined, Epsilon passes the contents of this variable to the program as its command line. When Epsilon needs to pass a command line to the program, it doesn't use INTERSHELLFLAGS. Instead, it inserts the contents of the CMDSHELLFLAGS variable before the command line you type.

The sequence %% in CMDSHELLFLAGS makes Epsilon interpolate the command line at that point, instead of adding it after the flags. Put a "d" after the %% to have Epsilon double backslashes in the command line until the first space; put "b" to have Epsilon change backslashes to slashes until the first space, or "a" to have Epsilon interpolate the command line as-is. A plain %% makes Epsilon guess: it uses "b" if the shell name ends in "sh", otherwise "a".

If Epsilon can't find a definition for INTERSHELLFLAGS or CMDSHELLFLAGS, it substitutes flags appropriate for the operating system. See the next section for more on these settings.

Standard bindings:

Ctrl-x Ctrl-e    push

   filter-region

   shell-command

Subtopics:

The Concurrent Process
Compiling From Epsilon

Previous Up Next
The Open With Epsilon Shell Extension Commands by Topic The Concurrent Process