How do you climb up the parent directory structure of a bash script?

Is t开发者_如何学JAVAhere a neater way of climbing up multiple directory levels from the location of a script.

This is what I currently have.

# get the full path of the script
D=$(cd ${0%/*} && echo $PWD/${0##*/})

D=$(dirname $D)
D=$(dirname $D)
D=$(dirname $D)

# second level parent directory of script
echo $D

I would like a neat way of finding the nth level. Any ideas other than putting in a for loop?

dir="/path/to/somewhere/interesting"
saveIFS=$IFS
IFS='/'
parts=($dir)
IFS=$saveIFS
level=${parts[3]}
echo "$level"    # output: somewhere

#!/bin/sh
ancestor() {
  local n=${1:-1}
  (for ((; n != 0; n--)); do cd $(dirname ${PWD}); done; pwd)
}

Usage:

 $ pwd
 /home/nix/a/b/c/d/e/f/g

 $ ancestor 3
 /home/nix/a/b/c/d

A solution without loops would be to use recursion. I wanted to find a config file for a script by traversing backwards up from my current working directory.

rtrav() { test -e $2/$1 && echo $2 || { test $2 != / && rtrav $1 `dirname $2`;}; }

To check if the current directory is in a GIT repo: rtrav .git $PWD

rtrav will check the existence of a filename given by the first argument in each parent folder of the one given as the second argument. Printing the directory path where the file was found or exiting with an error code if the file was not found.

The predicate (test -e $2/$1) could be swapped for checking of a counter that indicates the traversal depth.

If you're OK with including a Perl command:

$ pwd
/u1/myuser/dir3/dir4/dir5/dir6/dir7

The first command lists the directory containing first N (in my case 5) directories

$ perl-e 'use File::Spec; \
          my @dirs = File::Spec->splitdir( \
             File::Spec->rel2abs( File::Spec->curdir() ) ); \
          my @dirs2=@dirs[0..5]; print File::Spec->catdir(@dirs2) . "\n";'
/u1/myuser/dir3/dir4/dir5

The second command lists the directory N levels up (in my case 5) directories (I think you wanted the latter).

$ perl -e 'use File::Spec; \
           my @dirs = File::Spec->splitdir( \
              File::Spec->rel2abs( File::Spec->curdir() ) ); \
           my @dirs2=@dirs[0..$#dir-5]; print File::Spec->catdir(@dirs2)."\n";'
/u1/myuser

To use it in your bash script, of course:

D=$(perl -e 'use File::Spec; \
           my @dirs = File::Spec->splitdir( \
              File::Spec->rel2abs( File::Spec->curdir() ) ); \
           my @dirs2=@dirs[0..$#dir-5]; print File::Spec->catdir(@dirs2)."\n";')

Any ideas other than putting in a for loop?

In shells, you can't avoid the loop, because traditionally they do not support regexp, but glob matching instead. And glob patterns do not support the any sort of repeat counters.

And BTW, simplest way is to do it in shell is: echo $(cd $PWD/../.. && echo $PWD) where the /../.. makes it strip two levels.

With tiny bit of Perl that would be:

perl -e '$ENV{PWD} =~ m@^(.*)(/[^/]+){2}$@ && print $1,"\n"'

The {2} in the Perl's regular expression is the number of directory entries to strip. Or making it configurable:

N=2
perl -e '$ENV{PWD} =~ m@^(.*)(/[^/]+){'$N'}$@ && print $1,"\n"'

One can also use Perl's split(), join() and splice() for the purpose, e.g.:

perl -e '@a=split("/", $ENV{PWD}); print join("/", splice(@a, 0, -2)),"\n"'

where -2 says that from the path the last two entries has to be removed.

Two levels above the script directory:

echo "$(readlink -f -- "$(dirname -- "$0")/../..")"

All the quoting and -- are to avoid problems with tricky paths.

This method uses the actual full path to the perl script itself ... TIMTOWTDI You could just easily replace the $RunDir with the path you would like to start with ...

        #resolve the run dir where this scripts is placed
        $0 =~ m/^(.*)(\\|\/)(.*)\.([a-z]*)/; 
        $RunDir = $1 ; 
        #change the \'s to /'s if we are on Windows
        $RunDir =~s/\\/\//gi ; 
        my @DirParts = split ('/' , $RunDir) ; 
        for (my $count=0; $count < 4; $count++) {   pop @DirParts ;     }

        $confHolder->{'ProductBaseDir'} = $ProductBaseDir ; 

This allows you to work your way up until whatever condition is desired

WORKDIR=$PWD
until test -d "$WORKDIR/infra/codedeploy"; do
  # get the full path of the script

  WORKDIR=$(dirname $WORKDIR)
done