ealias

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#+TITLE: ealias README #+AUTHOR: Andreas Politz #+EMAIL: [email protected]

• Description

  The ealias command is in effect a wrapper around emacsclient for the Bash shell. It's a simple way of defining a shell function, which will in turn call a specific Emacs function with a number of given arguments. It gives a little bit of eshell feeling and is especially useful for mapping terminal-loving commands like ~man~ to their Emacs equivalents when using an M-x shell.

• Installation

  Somehow download the file ~ealias~ in some directory and source it either from your ~/.bashrc, for access in any shell, or your ~/.emacs_bash, if you prefer it only being active in the M-x shell.

• Usage

  After proper installation you should have access to a new command called ~ealias~. See the output of #+BEGIN_SRC sh $ ealias --help #+END_SRC for a complete description and the [[Examples]] section below.

** Environment Variables

There are a couple of variables which influence the behavior of the ~ealias~ command. They are listed in the following table and further described below.

| Variable | Default | Description | |---------------+--------------------+------------------------------------------| | EALIAS_RC | ~/.config/ealiasrc | Filename to use for the -w/-r/-e options | | EALIAS_CLIENT | emacsclient | Program to use as emacsclient | |---------------+--------------------+------------------------------------------|

For convenience the ~ealias~ options ~-w~, ~-r~ and ~-e~ let you write, resp. read, resp. edit the file ~EALIAS_RC~ . This is just an easy way to write your possibly interactively defined aliases to a file and read them back in later.

• Examples

  A ~ealias~ definition looks pretty much like a normal alias, except it

  • may contain a number of special format codes and
  • it is called much like a function, i.e. it accepts parameter.

  Let's start with a simple example and redefine the ~man~ command, which is pretty useless in an M-x shell. #+BEGIN_SRC sh $ ealias man='man %*' #+END_SRC

  The ~%*~ construct takes the remaining arguments (in this case all) and concatenates them into a single string. We can examine what would be executed with the ~-n~ option. #+BEGIN_SRC sh $ man -n 3 printf emacsclient --eval (man "3 printf") $ man 3 printf #<buffer Man 3 printf> #+END_SRC

  The next alias utilizes the ~diff~ command, which takes 3 arguments, namely the 2 files to find the differences for and which options to use. #+BEGIN_SRC sh $ ealias ediff='diff %^ %^ %*' #+END_SRC The ~%^~ code pops an argument and wraps it, like all ~%~-constructs, in double-quotes, thereby transforming the shell word into a Lisp string. #+BEGIN_SRC sh $ ediff -n file1 file2 -w -c emacsclient --eval (diff "file1" "file2" "-w -c") #+END_SRC
  The last example finds a file and edits it as the root user. #+BEGIN_SRC sh $ ealias redit='find-file-other-window "/sudo::$(readlink -f "$1")"' #+END_SRC Note, that this alias uses regular parameters only. Since the whole expression is evaluated, we need to escape the quotes.
  #+BEGIN_SRC sh $ redit -n /etc/bashrc emacsclient --eval (find-file-other-window "/sudo::/etc/bashrc") #+END_SRC See the file ~ealiasrc.example~ for more examples.