How do I get the absolute directory of a file in bash

Question

I have written a bash script that takes an input file as an argument and reads it  This file contains some paths  relative to its location  to additional files used    I would like the script to go to the folder containing the input file  to execute further commands     So  how do I get the folder  and just the folder  from an input file   In linux

User · Answer

I have been using readlink -f  works on linux  so  FULL PATH   readlink -f filename  DIR   dirname  FULL PATH   PWD   pwd   cd  DIR    lt do more work gt   cd  PWD

User · Answer

Try our new Bash library product realpath-lib over at GitHub that we have given to the community for free and unencumbered use   It s clean  simple and well documented so it s great to learn from   You can do     get realpath  lt absolute relative symlink local file path gt    This function is the core of the library     if    -f   1     then       file  must  exist     if cd    echo    1         amp  gt  dev null     then           file  may  not be local           exception is   file ext           try  cd    cd -    works           local tmppwd   PWD          cd -  amp  gt  dev null     else           file  must  be local         local tmppwd   PWD      fi else       file  cannot  exist     return 1   failure fi    reassemble realpath echo   tmppwd     1       return 0   success      It s Bash 4   does not require any dependencies and also provides get dirname  get filename  get stemname and validate path

User · Answer

This will work for both file and folder   absPath        if    -d   1      then         cd   1          echo    pwd -P       else          cd    dirname   1            echo    pwd -P    basename   1        fi

User · Answer

cat abs sh    bin bash echo    cd    dirname   1     pwd -P     Some explanations    This script get relative path as argument   1  Then we get dirname part of that path  you can pass either dir or file to this script   dirname   1  Then we cd    dirname   1    into this relative dir  pwd -P and get absolute path  The -P option will avoid symlinks As final step we echo it   Then run your script   abs sh your file txt

User · Answer

Problem with the above answer comes with files input with       like    my-file txt   Workaround  of many        myfile    somefile txt      FOLDER    dirname   readlink -f    ARG          echo   FOLDER

User · Answer

To get the full path use   readlink -f relative path to file   To get the directory of a file   dirname relative path to file   You can also combine the two   dirname   readlink -f relative path to file    If readlink -f is not available on your system you can use this    function myreadlink           cd    dirname  1             or  cd    1        echo   PWD   basename  1     or  echo   PWD   1               Note that if you only need to move to a directory of a file specified as a relative path  you don t need to know the absolute path  a relative path is perfectly legal  so just use   cd   dirname relative path to file    if you wish to go back  while the script is running  to the original path  use pushd instead of cd  and popd when you are done       While myreadlink above is good enough in the context of this question  it has some limitation relative to the readlink tool suggested above  For example it doesn t correctly follow a link to a file with different basename

User · Answer

Take a look at realpath which is available on GNU Linux  FreeBSD and NetBSD  but not OpenBSD 6 8  I use something like  CONTAININGDIR   realpath   FILEPATH       to do what it sounds like you re trying to do

[linux] How do I get the absolute directory of a file in bash?

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