Implementations of Shell Autocompletion

Back to Shell Autocompletion

bash

• GNU readline does ad hoc tokenization of the shell command. Does not use its parser.
• builtins: complete, compopt, compgen
• global variables: COMP_WORDS, COMPREPLY (out)

• completions maintained out of tree in bash-completion

yash

• lineedit/compparse.{c,h} (~1300 lines) is a "simple parser for command line completion" that duplicates knowledge of the shell language. It doesn't use its own parser much, if at all.
• help complete shows help for the extensive completion builtin. Doesn't seem to understand the flags of its own builtins.
• completions maintained in-tree in share/completion

As usual, git is one of the biggest completions!

~/src/languages/yash-2.46/share/completion$ wc -l *|sort -n
...
   497 git-config
   541 tar
   554 find
   597 git-svn
   657 INIT
   759 git
   850 svn
 19921 total

zsh

TODO

• completions maintained in-tree

fish

• has a complete builtin
• completions maintained in-tree