Why am I no more able to change the environment variable $USERNAME on macOS?












1















WHAT I WANT TO DO



$ echo $USERNAME

myusername

$ export USERNAME=newvalue

$ echo $USERNAME

newvalue


WHAT IS HAPPENING



$ echo $USERNAME

myusername

$ export USERNAME=newvalue

$ echo $USERNAME

myusername


WHAT I TRIED




  • I tried to use: sudo ...;

  • I tried to use: unset USERNAME.


USEFUL NOTES




  • OS: macOS Mojave 10.14


  • Direnv: https://github.com/direnv/direnv


  • I am using zsh



WHAT I DID BEFORE THE ISSUE



I was able to change my environment variable several times using direnv (https://github.com/direnv/direnv), and everything was working well.



I was able to set local env variables in .envrc.
Then, I encountered this issue...




SOLUTION



https://unix.stackexchange.com/questions/483469/cannot-change-the-environment-variable






macos environment-variables zsh iterm2 direnv







share|improve this question





























    1















    WHAT I WANT TO DO



    $ echo $USERNAME
    
myusername
    
$ export USERNAME=newvalue
    
$ echo $USERNAME
    
newvalue


    WHAT IS HAPPENING



    $ echo $USERNAME
    
myusername
    
$ export USERNAME=newvalue
    
$ echo $USERNAME
    
myusername


    WHAT I TRIED




    • I tried to use: sudo ...;

    • I tried to use: unset USERNAME.


    USEFUL NOTES




    • OS: macOS Mojave 10.14


    • Direnv: https://github.com/direnv/direnv


    • I am using zsh



    WHAT I DID BEFORE THE ISSUE



    I was able to change my environment variable several times using direnv (https://github.com/direnv/direnv), and everything was working well.



    I was able to set local env variables in .envrc.
    Then, I encountered this issue...




    SOLUTION



    https://unix.stackexchange.com/questions/483469/cannot-change-the-environment-variable






    macos environment-variables zsh iterm2 direnv







    share|improve this question



























      1












      1








      1








      WHAT I WANT TO DO



      $ echo $USERNAME
      
myusername
      
$ export USERNAME=newvalue
      
$ echo $USERNAME
      
newvalue


      WHAT IS HAPPENING



      $ echo $USERNAME
      
myusername
      
$ export USERNAME=newvalue
      
$ echo $USERNAME
      
myusername


      WHAT I TRIED




      • I tried to use: sudo ...;

      • I tried to use: unset USERNAME.


      USEFUL NOTES




      • OS: macOS Mojave 10.14


      • Direnv: https://github.com/direnv/direnv


      • I am using zsh



      WHAT I DID BEFORE THE ISSUE



      I was able to change my environment variable several times using direnv (https://github.com/direnv/direnv), and everything was working well.



      I was able to set local env variables in .envrc.
      Then, I encountered this issue...




      SOLUTION



      https://unix.stackexchange.com/questions/483469/cannot-change-the-environment-variable






      macos environment-variables zsh iterm2 direnv







      share|improve this question
















      WHAT I WANT TO DO



      $ echo $USERNAME
      
myusername
      
$ export USERNAME=newvalue
      
$ echo $USERNAME
      
newvalue


      WHAT IS HAPPENING



      $ echo $USERNAME
      
myusername
      
$ export USERNAME=newvalue
      
$ echo $USERNAME
      
myusername


      WHAT I TRIED




      • I tried to use: sudo ...;

      • I tried to use: unset USERNAME.


      USEFUL NOTES




      • OS: macOS Mojave 10.14


      • Direnv: https://github.com/direnv/direnv


      • I am using zsh



      WHAT I DID BEFORE THE ISSUE



      I was able to change my environment variable several times using direnv (https://github.com/direnv/direnv), and everything was working well.



      I was able to set local env variables in .envrc.
      Then, I encountered this issue...




      SOLUTION



      https://unix.stackexchange.com/questions/483469/cannot-change-the-environment-variable






      macos environment-variables zsh iterm2 direnv




      macos environment-variables zsh iterm2 direnv






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Dec 1 '18 at 16:52







      Riccardo Persiani

















      asked Nov 21 '18 at 18:18









      Riccardo PersianiRiccardo Persiani

      2751215




      2751215
























          1 Answer
          1






          active

          oldest

          votes


















          3














          In zsh the USERNAME var is magical. It is not a normal exported env var. From the man page:



             USERNAME <S>
          
          The username corresponding to the real user ID of the shell process.  If you
          
          have sufficient privileges, you may change the username (and also  the  user
          
          ID  and group ID) of the shell by assigning to this parameter.  Also (assum-
          
          ing sufficient privileges), you may start a single command under a different
          
          username (and user ID and group ID) by `(USERNAME=username; command)'


          In other shells, like bash and fish, this is not a special var and you can set it just like any other env var:



          bash$ echo $USERNAME
          

          
bash$ export USERNAME=wtf
          
bash$ echo $USERNAME
          
wtf





          share|improve this answer
























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            1 Answer
            1






            active

            oldest

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            1 Answer
            1






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            3














            In zsh the USERNAME var is magical. It is not a normal exported env var. From the man page:



               USERNAME <S>
            
          The username corresponding to the real user ID of the shell process.  If you
            
          have sufficient privileges, you may change the username (and also  the  user
            
          ID  and group ID) of the shell by assigning to this parameter.  Also (assum-
            
          ing sufficient privileges), you may start a single command under a different
            
          username (and user ID and group ID) by `(USERNAME=username; command)'


            In other shells, like bash and fish, this is not a special var and you can set it just like any other env var:



            bash$ echo $USERNAME
            

            
bash$ export USERNAME=wtf
            
bash$ echo $USERNAME
            
wtf





            share|improve this answer




























              3














              In zsh the USERNAME var is magical. It is not a normal exported env var. From the man page:



                 USERNAME <S>
              
          The username corresponding to the real user ID of the shell process.  If you
              
          have sufficient privileges, you may change the username (and also  the  user
              
          ID  and group ID) of the shell by assigning to this parameter.  Also (assum-
              
          ing sufficient privileges), you may start a single command under a different
              
          username (and user ID and group ID) by `(USERNAME=username; command)'


              In other shells, like bash and fish, this is not a special var and you can set it just like any other env var:



              bash$ echo $USERNAME
              

              
bash$ export USERNAME=wtf
              
bash$ echo $USERNAME
              
wtf





              share|improve this answer


























                3












                3








                3







                In zsh the USERNAME var is magical. It is not a normal exported env var. From the man page:



                   USERNAME <S>
                
          The username corresponding to the real user ID of the shell process.  If you
                
          have sufficient privileges, you may change the username (and also  the  user
                
          ID  and group ID) of the shell by assigning to this parameter.  Also (assum-
                
          ing sufficient privileges), you may start a single command under a different
                
          username (and user ID and group ID) by `(USERNAME=username; command)'


                In other shells, like bash and fish, this is not a special var and you can set it just like any other env var:



                bash$ echo $USERNAME
                

                
bash$ export USERNAME=wtf
                
bash$ echo $USERNAME
                
wtf





                share|improve this answer













                In zsh the USERNAME var is magical. It is not a normal exported env var. From the man page:



                   USERNAME <S>
                
          The username corresponding to the real user ID of the shell process.  If you
                
          have sufficient privileges, you may change the username (and also  the  user
                
          ID  and group ID) of the shell by assigning to this parameter.  Also (assum-
                
          ing sufficient privileges), you may start a single command under a different
                
          username (and user ID and group ID) by `(USERNAME=username; command)'


                In other shells, like bash and fish, this is not a special var and you can set it just like any other env var:



                bash$ echo $USERNAME
                

                
bash$ export USERNAME=wtf
                
bash$ echo $USERNAME
                
wtf






                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 30 '18 at 21:46









                Kurtis RaderKurtis Rader

                3,379610




                3,379610
































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