Editing bash scripts in emacs

sh-mode (aka shell-script-mode) is the default minor mode for editing Bash scripts. The source is on GitHub.

On my Ubuntu 18.04 install this is implemented in this file …

/usr/share/emacs/25.2/lisp/progmodes/sh-script.elc

This mode should autoload when editing .sh files.

Customization

Indentation is controlled by various variables. After much experimentation I have found that this is the magic incantation that I need in my .emacs file in order to have bash scripts indented the way I like …

(custom-set-variables
 ;; ...

 ;; sh-mode
 '(sh-basic-offset 2)
 '(sh-indentation 2)
 '(sh-indent-after-continuation 'always))

 ;; ... 
)

It seems that I need to set both sh-basic-offset and sh-indentation in order to achieve my desired indent across all situations in a script.

The last line is critical in order to ensure that I always have two space indenting after the line continuation character, e.g. …

docker run \
  --rm \
  --name prometheus \
  -d \
  -p 9090:9090 \
  prom/prometheus

The default behavior is for the first continuation line to be indented to line up with the first non-space character in the first line, i.e. like this …

docker run \
       --rm \
       --name prometheus \
       -d \
       -p 9090:9090 \
       prom/prometheus