iridakos / bash-completion-tutorial Goto Github PK

I'm creating a script that's supposed to manage a few files in the system. list them, create them, delete them.

I followed your bash completion guide but it does not mention working with arguments.

example: one of the commands of my script would be script remove <name>. name would be a file in a directory.

but other arguments would use the same completion, like script disable <name> and script enable <name>

how could I make it so that it works with multiple arguments?

thank you.

Hello, if I could autocomplete the param using fuzzy match?

params
hello
world

$ comp_test ld<tab><tab>
world

Thanks for the guide, I'm really grateful.
But could I suggest to you to change the dummy script to something maybe less potential harmful, for example:

if [ -z "$1" ]; then
  echo "No command number passed"
  exit 2
fi

exists=$(fc -l -1000 | grep ^$1 -- 2>/dev/null)

if [ -n "$exists" ]; then
  echo "This would have been executing the command:"
  echo fc -s -- "$1"
else
  echo "Command with number $1 was not found in recent history"
  exit 2
fi

Ran the history command to see what was in there and thought,- ups dothis could also work as an effective foot amputation device if entering the wrong number. 😲😀

I've been searching for a way to reliably install bash completions cross-platform. While many places do have a /etc/bash_completion.d directory, some have it mapped to strange places. My current solution is as follows in a makefile:

# Attempt to find bash completion dir in order of preference
ifneq ($(wildcard /etc/bash_completion.d/.),)
  CPLDIR ?= /etc/bash_completion.d
endif

# Check if brew in installed (OSX) and use brew prefix
HAS_BREW := $(shell command -v brew 2> /dev/null)
ifdef HAS_BREW
  CPLDIR ?= $$(brew --prefix)/etc/bash_completion.d
endif

# Last resort, check pkg-config for custom bash completion path
HAS_PKGCONFIG := $(shell command -v pkg-config 2> /dev/null)
ifdef HAS_PKGCONFIG
  CPLDIR ?= $$(pkg-config --variable=completionsdir bash-completion 2> /dev/null)
endif

and later in the recipe:

install:
	...
ifdef CPLDIR
	echo Installing the command completion to $(CPLDIR)
	@mkdir -p $(CPLDIR)
	cp -f program.d $(CPLDIR)/program
	chmod 644 $(CPLDIR)/program
endif

Have you seen any more thorough solutions? I still feel like this is a hack.

My setting in ~/.inputrc

set show-all-if-ambiguous on
#cycle through choices with ctrl-right/left
"\e[1;5C": menu-complete
"\e[1;5D": menu-complete-backward

When triggering menu-complete (see man bash) first word takes place (in not wanted format) immediately at the same time with showing suggestions

The problem with this implementation is that we get:

dothis <number> command_name <padding>
           <cursor>

What could we do to improve this behaviour? Thank you in advance!

Ok, I read about it a bit now and I understand: https://unix.stackexchange.com/questions/11376/what-does-double-dash-mean-also-known-as-bare-double-dash

It's there to signify we've finished listing the options and will now only add the prefix of the completion.

I don't know if you'd want to add a comment about it in the text.

Anyway Great Tutorial!

No way to tell you how grateful I am to you for this well-prepared tutorial, neither on GitHub nor on your blog site. So there is this issue: thank you. Feel free to close with no response :-)
Filippo

When working through the tutorial, once you begin using fc -l... in the completion script. You neglect to add the IFS=$'\n' to the script. This results in each command and number being broken apart into multiple unrelated "arguments".

Your code relies on word splitting suggestions=( $(compgen ... ) ) and the completion gives me wrong results before you set IFS=$'\n'. When you tested your function, you might have had IFS set from some previous attempts (since compgen also splits using IFS, I believe that really is the case). It's also subject to pathname expansion which is not that important here but still might be an issue in some extreme cases. set -f might be a good idea.

I believe that creating a completion that correctly handles whitespace characters and globs is extremely painful. I may have missed something of course and I might embarrass myself :) Overall it's a great article giving insight in some less known parts of bash 👍

((Thanks, https://iridakos.com/programming/2018/03/01/bash-programmable-completion-tutorial Is super-accessible, and very helpful!))

From this place in your doc

replace tabs with spaces ...
sed to the rescue.
... fc -l -50 | sed 's/\t//' ...

Actually removes the first plain "t" character!

Instead, to replace 1 tab character with 1 space,
the sed command you want is:

$ fc -l -50 | sed $'s/\t/ /'

Notes:

• Bash '' strings do not do C-style escape sequences
  • (neither to "" strings in Bash)
  • only $'' bash strings process C-style escape sequences
    • (recall that echo -e "a\tb" TAB expansion is done inside the echo builtin code)
• so sed sees '\t' in ARGV
  • which it interprets as:
    1. an unnecessary '\' character, then
    2. a plain 't' character
• Your sed removes what it matches, it does not replace
• Plain fc output already has 1 TAB and 1 SPACE between the num & command
• ...So it's really not clear if you want 1 space or 2 in the end result

Full log:

## Raw `fc` output:
## (using `... | cat -vet` to show TAB chars as "^I")
$ fc -l -5 | cat -vet
57^I . ~/ds/env/complete-dothis.bash $
58^I . ~/ds/env/complete-dothis.bash $
59^I _comp_debug_dothis=1$
60^I . ~/ds/env/complete-dothis.bash $
61^I dothis fc -l -5 | sed $'s/\t/ /'$

## Your current sed command:
## (note "complee", not complete")
$ fc -l -5 | sed 's/\t//' | cat -vet
58^I . ~/ds/env/complee-dothis.bash $
59^I _comp_debug_dohis=1$
60^I . ~/ds/env/complee-dothis.bash $
61^I dohis fc -l -5 | sed $'s/\t/ /'$
62^I fc -l -5 | ca -vet$

## Fixed sed command:
$ fc -l -5 | sed $'s/\t/ /' | cat -vet
59  _comp_debug_dothis=1$
60  . ~/ds/env/complete-dothis.bash $
61  dothis fc -l -5 | sed $'s/\t/ /'$
62  fc -l -5 | cat -vet$
63  fc -l -5 | sed 's/\t//' | cat -vet$
[12:43:57 Sun Feb 14] X:0 !65

$ echo "${BASH_VERSINFO[@]}"
3 2 57 1 release x86_64-apple-darwin18
# Mac 10.14.6

# ...but same behavior w/ Bash 5 (from HomeBrew)
5 0 18 1 release x86_64-apple-darwin18.7.0