clear out all variables without closing terminal












9















I want to know how to clear all variables which I defined in command prompt without closing terminal ?



for example, if I set a variable in command prompt as:



$ a=1


now I want to delete the variable $a (and many other variables defined in similar way) without closing terminal. I could use unset but it will be hectic if there are large no. of variables






shell environment-variables







share|improve this question




















  • 2





    exec "$0"maybe - but it's hard to tell what you mean by global.

    – mikeserv
    Dec 10 '14 at 23:07






  • 3





    Why do you want to do that?

    – Hauke Laging
    Dec 10 '14 at 23:12






  • 1





    @HaukeLaging I am working with arrays using script. I sometimes add one element to it. because of which I cant run the script with old values(since array is changed). i have to close the terminal and start a new session again. I hope I made clear. if not please let me know :)

    – Edward Torvalds
    Dec 10 '14 at 23:18








  • 1





    @muru - he gets a list saved to a $var with var=$(declare -p +F); then passes that as an argument to a function which does echo "${2%%=*}". That answer has a few problems with sheer size - but it should work if your environment isn't huge.

    – mikeserv
    Dec 10 '14 at 23:34






  • 3





    I have no idea what you're trying to do. Are you talking about an interactive shell or a script? Variables set in a script executed from an interactive shell don't affect the parent shell. Tell us what you want to achieve, not which dead end you're pursuing.

    – Gilles
    Dec 10 '14 at 23:49
















9















I want to know how to clear all variables which I defined in command prompt without closing terminal ?



for example, if I set a variable in command prompt as:



$ a=1


now I want to delete the variable $a (and many other variables defined in similar way) without closing terminal. I could use unset but it will be hectic if there are large no. of variables






shell environment-variables







share|improve this question




















  • 2





    exec "$0"maybe - but it's hard to tell what you mean by global.

    – mikeserv
    Dec 10 '14 at 23:07






  • 3





    Why do you want to do that?

    – Hauke Laging
    Dec 10 '14 at 23:12






  • 1





    @HaukeLaging I am working with arrays using script. I sometimes add one element to it. because of which I cant run the script with old values(since array is changed). i have to close the terminal and start a new session again. I hope I made clear. if not please let me know :)

    – Edward Torvalds
    Dec 10 '14 at 23:18








  • 1





    @muru - he gets a list saved to a $var with var=$(declare -p +F); then passes that as an argument to a function which does echo "${2%%=*}". That answer has a few problems with sheer size - but it should work if your environment isn't huge.

    – mikeserv
    Dec 10 '14 at 23:34






  • 3





    I have no idea what you're trying to do. Are you talking about an interactive shell or a script? Variables set in a script executed from an interactive shell don't affect the parent shell. Tell us what you want to achieve, not which dead end you're pursuing.

    – Gilles
    Dec 10 '14 at 23:49














9












9








9


1






I want to know how to clear all variables which I defined in command prompt without closing terminal ?



for example, if I set a variable in command prompt as:



$ a=1


now I want to delete the variable $a (and many other variables defined in similar way) without closing terminal. I could use unset but it will be hectic if there are large no. of variables






shell environment-variables







share|improve this question
















I want to know how to clear all variables which I defined in command prompt without closing terminal ?



for example, if I set a variable in command prompt as:



$ a=1


now I want to delete the variable $a (and many other variables defined in similar way) without closing terminal. I could use unset but it will be hectic if there are large no. of variables






shell environment-variables




shell environment-variables






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Dec 11 '14 at 0:40









Braiam

23.6k2077140




23.6k2077140










asked Dec 10 '14 at 23:06









Edward TorvaldsEdward Torvalds

2,59373263




2,59373263








  • 2





    exec "$0"maybe - but it's hard to tell what you mean by global.

    – mikeserv
    Dec 10 '14 at 23:07






  • 3





    Why do you want to do that?

    – Hauke Laging
    Dec 10 '14 at 23:12






  • 1





    @HaukeLaging I am working with arrays using script. I sometimes add one element to it. because of which I cant run the script with old values(since array is changed). i have to close the terminal and start a new session again. I hope I made clear. if not please let me know :)

    – Edward Torvalds
    Dec 10 '14 at 23:18








  • 1





    @muru - he gets a list saved to a $var with var=$(declare -p +F); then passes that as an argument to a function which does echo "${2%%=*}". That answer has a few problems with sheer size - but it should work if your environment isn't huge.

    – mikeserv
    Dec 10 '14 at 23:34






  • 3





    I have no idea what you're trying to do. Are you talking about an interactive shell or a script? Variables set in a script executed from an interactive shell don't affect the parent shell. Tell us what you want to achieve, not which dead end you're pursuing.

    – Gilles
    Dec 10 '14 at 23:49














  • 2





    exec "$0"maybe - but it's hard to tell what you mean by global.

    – mikeserv
    Dec 10 '14 at 23:07






  • 3





    Why do you want to do that?

    – Hauke Laging
    Dec 10 '14 at 23:12






  • 1





    @HaukeLaging I am working with arrays using script. I sometimes add one element to it. because of which I cant run the script with old values(since array is changed). i have to close the terminal and start a new session again. I hope I made clear. if not please let me know :)

    – Edward Torvalds
    Dec 10 '14 at 23:18








  • 1





    @muru - he gets a list saved to a $var with var=$(declare -p +F); then passes that as an argument to a function which does echo "${2%%=*}". That answer has a few problems with sheer size - but it should work if your environment isn't huge.

    – mikeserv
    Dec 10 '14 at 23:34






  • 3





    I have no idea what you're trying to do. Are you talking about an interactive shell or a script? Variables set in a script executed from an interactive shell don't affect the parent shell. Tell us what you want to achieve, not which dead end you're pursuing.

    – Gilles
    Dec 10 '14 at 23:49








2




2





exec "$0"maybe - but it's hard to tell what you mean by global.

– mikeserv
Dec 10 '14 at 23:07





exec "$0"maybe - but it's hard to tell what you mean by global.

– mikeserv
Dec 10 '14 at 23:07




3




3





Why do you want to do that?

– Hauke Laging
Dec 10 '14 at 23:12





Why do you want to do that?

– Hauke Laging
Dec 10 '14 at 23:12




1




1





@HaukeLaging I am working with arrays using script. I sometimes add one element to it. because of which I cant run the script with old values(since array is changed). i have to close the terminal and start a new session again. I hope I made clear. if not please let me know :)

– Edward Torvalds
Dec 10 '14 at 23:18







@HaukeLaging I am working with arrays using script. I sometimes add one element to it. because of which I cant run the script with old values(since array is changed). i have to close the terminal and start a new session again. I hope I made clear. if not please let me know :)

– Edward Torvalds
Dec 10 '14 at 23:18






1




1





@muru - he gets a list saved to a $var with var=$(declare -p +F); then passes that as an argument to a function which does echo "${2%%=*}". That answer has a few problems with sheer size - but it should work if your environment isn't huge.

– mikeserv
Dec 10 '14 at 23:34





@muru - he gets a list saved to a $var with var=$(declare -p +F); then passes that as an argument to a function which does echo "${2%%=*}". That answer has a few problems with sheer size - but it should work if your environment isn't huge.

– mikeserv
Dec 10 '14 at 23:34




3




3





I have no idea what you're trying to do. Are you talking about an interactive shell or a script? Variables set in a script executed from an interactive shell don't affect the parent shell. Tell us what you want to achieve, not which dead end you're pursuing.

– Gilles
Dec 10 '14 at 23:49





I have no idea what you're trying to do. Are you talking about an interactive shell or a script? Variables set in a script executed from an interactive shell don't affect the parent shell. Tell us what you want to achieve, not which dead end you're pursuing.

– Gilles
Dec 10 '14 at 23:49










2 Answers
2






active

oldest

votes


















9














If you do



exec bash


you will use a fresh & new environnement






share|improve this answer
























  • what about exec "$0" ?

    – Edward Torvalds
    Dec 11 '14 at 21:04











  • @edwardtorvalds $0 is the zeroth argument to an executed shell. So, if you're running bash $0 is bash (probably - it might be -bash in a -login shell case depending on version). If you're running a script with a #!/bin/bash bangline, $0 is the path to the script. exec "$0" is probably more flexible, but exec bash is more explicit. If you enter that command at a terminal, bash should recognize it's in an interactive environment and do the equivalent of bash -i - which will get your ~/.bashrc file run as well.

    – mikeserv
    Dec 11 '14 at 21:32





















0














You could use env, which is provided by GNU coreutils (typically preinstalled on GNU/Linux systems):



exec env --ignore-environment "$0"



The exec system call is so that your current process is replaced in-place by the new, environment-less version of your shell.



This has the benefit to also clear any exported environment variables.






share|improve this answer























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    2 Answers
    2






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    2 Answers
    2






    active

    oldest

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    active

    oldest

    votes






    active

    oldest

    votes









    9














    If you do



    exec bash


    you will use a fresh & new environnement






    share|improve this answer
























    • what about exec "$0" ?

      – Edward Torvalds
      Dec 11 '14 at 21:04











    • @edwardtorvalds $0 is the zeroth argument to an executed shell. So, if you're running bash $0 is bash (probably - it might be -bash in a -login shell case depending on version). If you're running a script with a #!/bin/bash bangline, $0 is the path to the script. exec "$0" is probably more flexible, but exec bash is more explicit. If you enter that command at a terminal, bash should recognize it's in an interactive environment and do the equivalent of bash -i - which will get your ~/.bashrc file run as well.

      – mikeserv
      Dec 11 '14 at 21:32


















    9














    If you do



    exec bash


    you will use a fresh & new environnement






    share|improve this answer
























    • what about exec "$0" ?

      – Edward Torvalds
      Dec 11 '14 at 21:04











    • @edwardtorvalds $0 is the zeroth argument to an executed shell. So, if you're running bash $0 is bash (probably - it might be -bash in a -login shell case depending on version). If you're running a script with a #!/bin/bash bangline, $0 is the path to the script. exec "$0" is probably more flexible, but exec bash is more explicit. If you enter that command at a terminal, bash should recognize it's in an interactive environment and do the equivalent of bash -i - which will get your ~/.bashrc file run as well.

      – mikeserv
      Dec 11 '14 at 21:32
















    9












    9








    9







    If you do



    exec bash


    you will use a fresh & new environnement






    share|improve this answer













    If you do



    exec bash


    you will use a fresh & new environnement







    share|improve this answer












    share|improve this answer



    share|improve this answer










    answered Dec 11 '14 at 19:46









    Gilles QuenotGilles Quenot

    16.2k13951




    16.2k13951













    • what about exec "$0" ?

      – Edward Torvalds
      Dec 11 '14 at 21:04











    • @edwardtorvalds $0 is the zeroth argument to an executed shell. So, if you're running bash $0 is bash (probably - it might be -bash in a -login shell case depending on version). If you're running a script with a #!/bin/bash bangline, $0 is the path to the script. exec "$0" is probably more flexible, but exec bash is more explicit. If you enter that command at a terminal, bash should recognize it's in an interactive environment and do the equivalent of bash -i - which will get your ~/.bashrc file run as well.

      – mikeserv
      Dec 11 '14 at 21:32





















    • what about exec "$0" ?

      – Edward Torvalds
      Dec 11 '14 at 21:04











    • @edwardtorvalds $0 is the zeroth argument to an executed shell. So, if you're running bash $0 is bash (probably - it might be -bash in a -login shell case depending on version). If you're running a script with a #!/bin/bash bangline, $0 is the path to the script. exec "$0" is probably more flexible, but exec bash is more explicit. If you enter that command at a terminal, bash should recognize it's in an interactive environment and do the equivalent of bash -i - which will get your ~/.bashrc file run as well.

      – mikeserv
      Dec 11 '14 at 21:32



















    what about exec "$0" ?

    – Edward Torvalds
    Dec 11 '14 at 21:04





    what about exec "$0" ?

    – Edward Torvalds
    Dec 11 '14 at 21:04













    @edwardtorvalds $0 is the zeroth argument to an executed shell. So, if you're running bash $0 is bash (probably - it might be -bash in a -login shell case depending on version). If you're running a script with a #!/bin/bash bangline, $0 is the path to the script. exec "$0" is probably more flexible, but exec bash is more explicit. If you enter that command at a terminal, bash should recognize it's in an interactive environment and do the equivalent of bash -i - which will get your ~/.bashrc file run as well.

    – mikeserv
    Dec 11 '14 at 21:32







    @edwardtorvalds $0 is the zeroth argument to an executed shell. So, if you're running bash $0 is bash (probably - it might be -bash in a -login shell case depending on version). If you're running a script with a #!/bin/bash bangline, $0 is the path to the script. exec "$0" is probably more flexible, but exec bash is more explicit. If you enter that command at a terminal, bash should recognize it's in an interactive environment and do the equivalent of bash -i - which will get your ~/.bashrc file run as well.

    – mikeserv
    Dec 11 '14 at 21:32















    0














    You could use env, which is provided by GNU coreutils (typically preinstalled on GNU/Linux systems):



    exec env --ignore-environment "$0"



    The exec system call is so that your current process is replaced in-place by the new, environment-less version of your shell.



    This has the benefit to also clear any exported environment variables.






    share|improve this answer




























      0














      You could use env, which is provided by GNU coreutils (typically preinstalled on GNU/Linux systems):



      exec env --ignore-environment "$0"



      The exec system call is so that your current process is replaced in-place by the new, environment-less version of your shell.



      This has the benefit to also clear any exported environment variables.






      share|improve this answer


























        0












        0








        0







        You could use env, which is provided by GNU coreutils (typically preinstalled on GNU/Linux systems):



        exec env --ignore-environment "$0"



        The exec system call is so that your current process is replaced in-place by the new, environment-less version of your shell.



        This has the benefit to also clear any exported environment variables.






        share|improve this answer













        You could use env, which is provided by GNU coreutils (typically preinstalled on GNU/Linux systems):



        exec env --ignore-environment "$0"



        The exec system call is so that your current process is replaced in-place by the new, environment-less version of your shell.



        This has the benefit to also clear any exported environment variables.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 21 mins ago









        user30747user30747

        1212




        1212






























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