Changing directory in script doesn't change directory — why?












1














I've seen this answer since searching for this, but initially I wrote this script:



for i in `seq 1 $1`; 
do cd ../;
done;


It doesn't change directory. Why is this, running as



./updir.sh 5









share|improve this question
























  • Thanks guys. I've gone with the function solution with: function updir() { a=""; for i in seq 1 $1; do a=$a"../"; done; cd $a; }. This allows use of cd - as expected.
    – David Boshton
    Dec 6 at 17:39


















1














I've seen this answer since searching for this, but initially I wrote this script:



for i in `seq 1 $1`; 
do cd ../;
done;


It doesn't change directory. Why is this, running as



./updir.sh 5









share|improve this question
























  • Thanks guys. I've gone with the function solution with: function updir() { a=""; for i in seq 1 $1; do a=$a"../"; done; cd $a; }. This allows use of cd - as expected.
    – David Boshton
    Dec 6 at 17:39
















1












1








1







I've seen this answer since searching for this, but initially I wrote this script:



for i in `seq 1 $1`; 
do cd ../;
done;


It doesn't change directory. Why is this, running as



./updir.sh 5









share|improve this question















I've seen this answer since searching for this, but initially I wrote this script:



for i in `seq 1 $1`; 
do cd ../;
done;


It doesn't change directory. Why is this, running as



./updir.sh 5






bash bash-scripting






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 6 at 16:34

























asked Dec 6 at 16:15









David Boshton

1104




1104












  • Thanks guys. I've gone with the function solution with: function updir() { a=""; for i in seq 1 $1; do a=$a"../"; done; cd $a; }. This allows use of cd - as expected.
    – David Boshton
    Dec 6 at 17:39




















  • Thanks guys. I've gone with the function solution with: function updir() { a=""; for i in seq 1 $1; do a=$a"../"; done; cd $a; }. This allows use of cd - as expected.
    – David Boshton
    Dec 6 at 17:39


















Thanks guys. I've gone with the function solution with: function updir() { a=""; for i in seq 1 $1; do a=$a"../"; done; cd $a; }. This allows use of cd - as expected.
– David Boshton
Dec 6 at 17:39






Thanks guys. I've gone with the function solution with: function updir() { a=""; for i in seq 1 $1; do a=$a"../"; done; cd $a; }. This allows use of cd - as expected.
– David Boshton
Dec 6 at 17:39












2 Answers
2






active

oldest

votes


















5














Running a script as you show creates a copied environment in a sub-shell, and any changes you make, such as setting directories or environment variables, affect only this sub-shell environment, not the calling shell.



In order to make changes to the current shell from a script, you must run the script within the current shell using the source or . command:



. ./updir.sh 5


You can make this automatic with an alias:



alias updir='. ./updir.sh'


Alternatively, you can use a function instead of a script:



updir()
{ for i in `seq 1 $1`;
do cd ../;
done
}





share|improve this answer





























    2














    Because scripts are run in a subshell, which keeps track of the current working directory separately. The simplest solution is to use a function:



    function updir() {
    for i in $(seq 1 $1); do
    cd ..
    done
    }





    share|improve this answer



















    • 1




      Sorry, my answer crossed with yours, but I am leaving mine because I gave some extra details.
      – AFH
      Dec 6 at 16:33











    Your Answer








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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    5














    Running a script as you show creates a copied environment in a sub-shell, and any changes you make, such as setting directories or environment variables, affect only this sub-shell environment, not the calling shell.



    In order to make changes to the current shell from a script, you must run the script within the current shell using the source or . command:



    . ./updir.sh 5


    You can make this automatic with an alias:



    alias updir='. ./updir.sh'


    Alternatively, you can use a function instead of a script:



    updir()
    { for i in `seq 1 $1`;
    do cd ../;
    done
    }





    share|improve this answer


























      5














      Running a script as you show creates a copied environment in a sub-shell, and any changes you make, such as setting directories or environment variables, affect only this sub-shell environment, not the calling shell.



      In order to make changes to the current shell from a script, you must run the script within the current shell using the source or . command:



      . ./updir.sh 5


      You can make this automatic with an alias:



      alias updir='. ./updir.sh'


      Alternatively, you can use a function instead of a script:



      updir()
      { for i in `seq 1 $1`;
      do cd ../;
      done
      }





      share|improve this answer
























        5












        5








        5






        Running a script as you show creates a copied environment in a sub-shell, and any changes you make, such as setting directories or environment variables, affect only this sub-shell environment, not the calling shell.



        In order to make changes to the current shell from a script, you must run the script within the current shell using the source or . command:



        . ./updir.sh 5


        You can make this automatic with an alias:



        alias updir='. ./updir.sh'


        Alternatively, you can use a function instead of a script:



        updir()
        { for i in `seq 1 $1`;
        do cd ../;
        done
        }





        share|improve this answer












        Running a script as you show creates a copied environment in a sub-shell, and any changes you make, such as setting directories or environment variables, affect only this sub-shell environment, not the calling shell.



        In order to make changes to the current shell from a script, you must run the script within the current shell using the source or . command:



        . ./updir.sh 5


        You can make this automatic with an alias:



        alias updir='. ./updir.sh'


        Alternatively, you can use a function instead of a script:



        updir()
        { for i in `seq 1 $1`;
        do cd ../;
        done
        }






        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Dec 6 at 16:30









        AFH

        13.9k31938




        13.9k31938

























            2














            Because scripts are run in a subshell, which keeps track of the current working directory separately. The simplest solution is to use a function:



            function updir() {
            for i in $(seq 1 $1); do
            cd ..
            done
            }





            share|improve this answer



















            • 1




              Sorry, my answer crossed with yours, but I am leaving mine because I gave some extra details.
              – AFH
              Dec 6 at 16:33
















            2














            Because scripts are run in a subshell, which keeps track of the current working directory separately. The simplest solution is to use a function:



            function updir() {
            for i in $(seq 1 $1); do
            cd ..
            done
            }





            share|improve this answer



















            • 1




              Sorry, my answer crossed with yours, but I am leaving mine because I gave some extra details.
              – AFH
              Dec 6 at 16:33














            2












            2








            2






            Because scripts are run in a subshell, which keeps track of the current working directory separately. The simplest solution is to use a function:



            function updir() {
            for i in $(seq 1 $1); do
            cd ..
            done
            }





            share|improve this answer














            Because scripts are run in a subshell, which keeps track of the current working directory separately. The simplest solution is to use a function:



            function updir() {
            for i in $(seq 1 $1); do
            cd ..
            done
            }






            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited Dec 6 at 16:35









            Kamil Maciorowski

            24k155176




            24k155176










            answered Dec 6 at 16:27









            Program man

            1211




            1211








            • 1




              Sorry, my answer crossed with yours, but I am leaving mine because I gave some extra details.
              – AFH
              Dec 6 at 16:33














            • 1




              Sorry, my answer crossed with yours, but I am leaving mine because I gave some extra details.
              – AFH
              Dec 6 at 16:33








            1




            1




            Sorry, my answer crossed with yours, but I am leaving mine because I gave some extra details.
            – AFH
            Dec 6 at 16:33




            Sorry, my answer crossed with yours, but I am leaving mine because I gave some extra details.
            – AFH
            Dec 6 at 16:33


















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