CODEWITHSUNDEEP
linuxbashshell
SaburoutaMishima
SaburoutaMishima

Reputation: 267

How do I readlink a path from a variable?

This always returns nothing: readlink $Somevar. I can have "${Somevar}", "$Somevar", $Somevar, or ${Somevar} - it makes no difference. I keep printing Somevar and I know it has a sane value. Just entering $Somevar at the terminal (once I echo/"debug" my script to give me the relative path and abort) gives me the absolute path. But I need to be able to get the absolute path within the script!

Is it possible at all to use readlink in conjunction with a variable? I frankly have no idea how readlink even "knows" that it is being passed a variable. I thought even in a script it would be expanded by the shell before readlink was called. I've tested it in the terminal (sans scripts) with "~/_src". The only way it works is if I write that with no quotes. But if I assign that value to a variable every other function on my machine works with it BUT readlink.

How can I get the absolute path? I don't even care if I use readlink. I just want to get the absolute path from relative in a script.

UPDATE: (Stackoverflow comments broken)

I tagged as Linux. I asked for readlink because I also want to translate symlinks, but I am fine doing that in a separate step.

Also, this fails as well: ABSDIR=`cd $RELDIR; pwd` gives

bash: cd: ~/_src/: No such file or directory

(Which there is such a directory, and cd will find it if I type that exact dirname on the terminal.) I am now guessing that ~/ is expanded by the terminal itself.

So, is there no way to handle paths like that? Apprently all the utilities I thought handled these paths, were only working because the terminal expands the path before calling them.

Upvotes: 3

Views: 6148

Answers (2)

Bentoy13
Bentoy13

Reputation: 4974

On Cygwin, I have the same behaviour, so I append some readlink flag, such as -f, and it works fine:

readlink -f $Somevar

Upvotes: 2

Amadan
Amadan

Reputation: 198436

First of all, readlink does something slightly different on Linux or on OSX. Tagging your question with an OS rather than bash is a better idea, especially since readlink is not a bash builtin, but rather an executable.

Secondly, if you want to get an absolute path, why is that not the title of your question?

The easy and portable way to get an absolute path of a directory is 

ABSDIR=`cd $RELDIR; pwd`

Files are a little more work:

ABSFILE=`cd $(dirname $RELFILE); pwd`/`basename $RELFILE`

Upvotes: 5

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