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Bash auto-complete of environment variables

Recently I reinstalled ubuntu and I noticed a small but annoying problem with auto complete.

Say I have a $SOME_DIR variable. If I type $SOME and hit tab I get

Code:

cd \$SOME_DIR

it appends a slash at the beginning, which i don't want.

Second, if I use an env variable with any other command, e.g. ls, the auto complete isn't triggered at all..

I haven't come across this problem before and would appreciate any pointers.

Thanks in advance,

armandino

first try looking into each text file at /etc/bash_completion.d

then turn on hidden files and look at /home/yourname/bash"stuff" I have 6 files there

if none of that works and you know the exact phrase, since you only say it could be
$SOME_DIR....whatever it is ....try grep but that may take a long time or find

eg find /etc -type f -print |xargs grep -n "$SOME_DIR"

try a "zzz" first to see it should produce nil result...meaning it aint there.

Hi,

Thanks for the tips.

I think I may not have described the problem clearly. The problem is that bash escapes the dollar sign of an environment variable when I use the cd command. $SOME_DIR was just an example. It could be any variable.

To explain again, say the environment variable points to some directory

Quote:

export SOME_DIR=/path/to/some/directory

Now if I type 'cd $SOME_D' and hit tab for autocompletion, I get this

Quote:

cd \$SOME_DIR

(note the slash appended by the shell) instead of this

Quote:

cd $SOME_DIR

So my question is, how I can modify shell's autocompletion so it doesn't escape the dollar sign with a slash?

please report your post to a moderator and ask them to move it to a programming forum cos I can not help. Sorry to have mislead you.

Hey, no worries. I appreciate your help.

Mods, if you feel there's a more appropriate forum for this question, please move it there :)

I haven't found a proper solution to this, but there's a workaround. The escaping of environment variables can be disabled by pressing Esc followed by tab.

For example,

Code:

# cd $SO + [Esc] + [Tab]

# cd $SOME_DIR

If anyone knows a proper solution (i.e. without having to it Esc), please post it.

Quick Answer

Code:

shopt -s cdable_vars

complete -v -F _cd $nospace $filenames cd

This will give an instant, but temporary solution.

Short Answer
Put "shopt -s cdable_vars" in a start-up script. -- This will give a permanent solution. I haven't done this yet, not sure which one to use.

Context
I am still running SimplyMEPIS 3.3.2 -- based on Debian Etch, back when it was "Testing", not "Stable" as it is now. All of this is based on what I found on my own system.

Notes

"cd $SO + [Esc] + [Tab]" didn't work for me.
I started w/ /etc/bash_completion, not its companion directory. It's a large file:

Code:

$ wc /etc/bash_completion 8039 26553 188168 /etc/bash_completion

Key Clue
(From less -SN /etc/bash_completion)

Code:

  3000 if shopt -q cdable_vars; then

  3001    complete -v -F _cd $nospace $filenames cd

  3002 else

  3003    complete -F _cd $nospace $filenames cd

  3004 fi

References

Code:

$ help complete

Run man bash, then search for:

Completing
Programmable Completion
compgen [
complete [

Also from less -SN /etc/bash_completion:

Code:

 5 #  Copyright (C) Ian Macdonald <ian@caliban.org>



21 #  The latest version of this software can be obtained here:

22 #

23 #  http://www.caliban.org/bash/index.shtml#completion

Off Topic Discoveries
1. OMG, MEPIS has a "service" (ser<TAB>) cmd., & also "invoke-rc.d" (inv<TAB>). -- Check out their man pages.

2.

Code:

$ umount <TAB><TAB>

/                        /dev/shm                  /proc/sys/fs/binfmt_misc

/200                      /mnt/iso                  /sys

/Common                  /proc

/dev/pts                  /proc/bus/usb

Q: can /dev/pts, /dev/shm, /proc/*, or /sys be usefully umounted? -- I.E., is this a bug?

Hi!

Thanks for posting the solution. It worked perfectly well.

I think the complete command could do with more documentation. It has no man page or help output other than a two-line usage information.

Re:

Quote:

can /dev/pts, /dev/shm, /proc/*, or /sys be usefully umounted? -- I.E., is this a bug?

I've never tried or had to unmount any of them, but I did a quick search and found an interesting blog post that describes a situation where you would do that.

Also, from the man page:

Code:

      -a    All  of  the  file systems described in /etc/mtab are unmounted.

              (With umount version 2.7 and later: the proc filesystem  is  not

              unmounted.)

Arman

AFAIK, only external commands (config files etc.) have man pages. Because it is a bash built-in, complete is documented inside the (incredibly long) bash man page. That is why I gave you the following search phrases:

Quote:

Originally Posted by archtoad6 (Post 3055141)

Run man bash, then search for:

Completing
Programmable Completion
compgen [
complete [

Each will take to an appropriate place in the bash man page. Use the whole phrase, I designed it to get you to the exact place I intended.

Code:

help complete

is only supposed to present a reminder on the command line when you need to jog your memory.

To the original poster's issue, his problem is likely because dash rather than bash is configured as the default shell.

Just run 'sudo dpkg-reconfigure dash' and when prompted do not set dash as default.

SOLUTION for Ubuntu 12.04

This bug (tab complete not working on environment variables) is present in Ubuntu 12.04. It is a bug in bash-4.2. Applying patch bash4.2-029 solves the problem. See https://bugs.launchpad.net/ubuntu/+s...27/comments/14

It is also happening in Linux Mint 14 nadia. I used variables a lot and this is
starting to put me off! What is the best way to solve this ?