Cannot change the environment variable
up vote
4
down vote
favorite
WHAT I AM USING
- zsh
- MacOS Mojave 14.10
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
Tried to set USERNAME in .bashrc, .zshrc, .profile and nothing changes...
Tried to unset and reset and nothing changes...
osx zsh environment-variables
asked Nov 22 at 15:17
Riccardo Persiani
1235
New contributor
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
|
show 3 more comments
up vote
4
down vote
favorite
WHAT I AM USING
- zsh
- MacOS Mojave 14.10
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
Tried to set USERNAME in .bashrc, .zshrc, .profile and nothing changes...
Tried to unset and reset and nothing changes...
osx zsh environment-variables
asked Nov 22 at 15:17
Riccardo Persiani
1235
New contributor
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
This variable is readonly and you can change it by switching user
– Romeo Ninov
Nov 22 at 15:26
The weird thing is I am quite sure that I was able to change it, then I had probably messed up with something..
– Riccardo Persiani
Nov 22 at 15:27
Do you seereadonly USERNAMEordeclare -r USERNAMEanywhere? Either of those would mark a variable as read-only.
– telcoM
Nov 22 at 15:29
1
This is not a variable that is set by default on macOS. Are you setting it yourself somewhere?
– Kusalananda
Nov 22 at 15:38
2
what doestypeset -p USERNAMEsay?
– mosvy
Nov 22 at 15:38
|
show 3 more comments
up vote
4
down vote
favorite
up vote
4
down vote
favorite
WHAT I AM USING
- zsh
- MacOS Mojave 14.10
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
Tried to set USERNAME in .bashrc, .zshrc, .profile and nothing changes...
Tried to unset and reset and nothing changes...
osx zsh environment-variables
asked Nov 22 at 15:17
Riccardo Persiani
1235
New contributor
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
WHAT I AM USING
- zsh
- MacOS Mojave 14.10
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
Tried to set USERNAME in .bashrc, .zshrc, .profile and nothing changes...
Tried to unset and reset and nothing changes...
osx zsh environment-variables
osx zsh environment-variables
asked Nov 22 at 15:17
Riccardo Persiani
1235
New contributor
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Nov 22 at 15:17
Riccardo Persiani
1235
New contributor
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited Nov 22 at 16:36
asked Nov 22 at 15:17
Riccardo Persiani
1235
New contributor
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Nov 22 at 15:17
Riccardo Persiani
1235
asked Nov 22 at 15:17
Riccardo Persiani
1235
1235
New contributor
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Riccardo Persiani is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
This variable is readonly and you can change it by switching user
– Romeo Ninov
Nov 22 at 15:26
The weird thing is I am quite sure that I was able to change it, then I had probably messed up with something..
– Riccardo Persiani
Nov 22 at 15:27
Do you seereadonly USERNAMEordeclare -r USERNAMEanywhere? Either of those would mark a variable as read-only.
– telcoM
Nov 22 at 15:29
1
This is not a variable that is set by default on macOS. Are you setting it yourself somewhere?
– Kusalananda
Nov 22 at 15:38
2
what doestypeset -p USERNAMEsay?
– mosvy
Nov 22 at 15:38
|
show 3 more comments
This variable is readonly and you can change it by switching user
– Romeo Ninov
Nov 22 at 15:26
The weird thing is I am quite sure that I was able to change it, then I had probably messed up with something..
– Riccardo Persiani
Nov 22 at 15:27
Do you seereadonly USERNAMEordeclare -r USERNAMEanywhere? Either of those would mark a variable as read-only.
– telcoM
Nov 22 at 15:29
1
This is not a variable that is set by default on macOS. Are you setting it yourself somewhere?
– Kusalananda
Nov 22 at 15:38
2
what doestypeset -p USERNAMEsay?
– mosvy
Nov 22 at 15:38
This variable is readonly and you can change it by switching user
– Romeo Ninov
Nov 22 at 15:26
This variable is readonly and you can change it by switching user
– Romeo Ninov
Nov 22 at 15:26
The weird thing is I am quite sure that I was able to change it, then I had probably messed up with something..
– Riccardo Persiani
Nov 22 at 15:27
The weird thing is I am quite sure that I was able to change it, then I had probably messed up with something..
– Riccardo Persiani
Nov 22 at 15:27
Do you see
readonly USERNAME or declare -r USERNAME anywhere? Either of those would mark a variable as read-only.– telcoM
Nov 22 at 15:29
Do you see
readonly USERNAME or declare -r USERNAME anywhere? Either of those would mark a variable as read-only.– telcoM
Nov 22 at 15:29
1
1
This is not a variable that is set by default on macOS. Are you setting it yourself somewhere?
– Kusalananda
Nov 22 at 15:38
This is not a variable that is set by default on macOS. Are you setting it yourself somewhere?
– Kusalananda
Nov 22 at 15:38
2
2
what does
typeset -p USERNAME say?– mosvy
Nov 22 at 15:38
what does
typeset -p USERNAME say?– mosvy
Nov 22 at 15:38
|
show 3 more comments
1 Answer
1
active
oldest
votes
up vote
12
down vote
accepted
The USERNAME shell variable is special in the Z shell.
It is always the account name of the user ID of the shell process.
You won't observe the behaviour that you observed in the Almquist, Watanabe, Korn, or Bourne Again shells. This variable is just an ordinary shell variable, that starts out unset, as far as they are concerned. Here's the 93 Korn shell, for example:
$ echo $USERNAME
$ USERNAME=wibble
$ echo $USERNAME
wibble
$
In the Z shell it starts out as the account name of the UID of the shell process. An attempt to set it will attempt to change that UID. This of course fails if you are not the superuser and leaves the variable back as it was before.
If you had run the Z shell as the superuser, however, you would have seen both the USERNAME shell variable and your shell process's user ID change.
root # echo $USERNAME
root
root # USERNAME=JdeBP
JdeBP %
Further reading
- Paul Falstad et al. (2015-12-02). "Parameters Set By The Shell". Z Shell Manual. 5.2.
answered Nov 22 at 15:47
JdeBP
31.8k467148
Running as a superuser I am able to change the variable. Thank you
– Riccardo Persiani
Nov 22 at 15:54
2
@RiccardoPersiani Ummm... switching to root is not a "solution". Why do you need to change the value of this variable?
– Kusalananda
Nov 22 at 16:10
I agree. However, I also can change it, simply switching from zsh to bash.
– Riccardo Persiani
Nov 22 at 16:34
2
Note that there can be more than one user name for a user id,zshreports the one returned bygetpwuid()so an arbitrary one (one could argue it should uselogname()instead). Changing$USERNAMEdoes asetuid(), but alsosetgid()/setgroups()with the groups mentioned in the user database as when you log in as that user name, that's different from setting$UIDor$EUIDfor instance. So by doing aUSERNAME=$USERNAMEyou might very well change the list of groups of the process if there are several usernames for the current uid with different group membership.
– Stéphane Chazelas
Nov 22 at 17:50
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
12
down vote
accepted
The USERNAME shell variable is special in the Z shell.
It is always the account name of the user ID of the shell process.
You won't observe the behaviour that you observed in the Almquist, Watanabe, Korn, or Bourne Again shells. This variable is just an ordinary shell variable, that starts out unset, as far as they are concerned. Here's the 93 Korn shell, for example:
$ echo $USERNAME
$ USERNAME=wibble
$ echo $USERNAME
wibble
$
In the Z shell it starts out as the account name of the UID of the shell process. An attempt to set it will attempt to change that UID. This of course fails if you are not the superuser and leaves the variable back as it was before.
If you had run the Z shell as the superuser, however, you would have seen both the USERNAME shell variable and your shell process's user ID change.
root # echo $USERNAME
root
root # USERNAME=JdeBP
JdeBP %
Further reading
- Paul Falstad et al. (2015-12-02). "Parameters Set By The Shell". Z Shell Manual. 5.2.
answered Nov 22 at 15:47
JdeBP
31.8k467148
Running as a superuser I am able to change the variable. Thank you
– Riccardo Persiani
Nov 22 at 15:54
2
@RiccardoPersiani Ummm... switching to root is not a "solution". Why do you need to change the value of this variable?
– Kusalananda
Nov 22 at 16:10
I agree. However, I also can change it, simply switching from zsh to bash.
– Riccardo Persiani
Nov 22 at 16:34
2
Note that there can be more than one user name for a user id,zshreports the one returned bygetpwuid()so an arbitrary one (one could argue it should uselogname()instead). Changing$USERNAMEdoes asetuid(), but alsosetgid()/setgroups()with the groups mentioned in the user database as when you log in as that user name, that's different from setting$UIDor$EUIDfor instance. So by doing aUSERNAME=$USERNAMEyou might very well change the list of groups of the process if there are several usernames for the current uid with different group membership.
– Stéphane Chazelas
Nov 22 at 17:50
add a comment |
up vote
12
down vote
accepted
The USERNAME shell variable is special in the Z shell.
It is always the account name of the user ID of the shell process.
You won't observe the behaviour that you observed in the Almquist, Watanabe, Korn, or Bourne Again shells. This variable is just an ordinary shell variable, that starts out unset, as far as they are concerned. Here's the 93 Korn shell, for example:
$ echo $USERNAME
$ USERNAME=wibble
$ echo $USERNAME
wibble
$
In the Z shell it starts out as the account name of the UID of the shell process. An attempt to set it will attempt to change that UID. This of course fails if you are not the superuser and leaves the variable back as it was before.
If you had run the Z shell as the superuser, however, you would have seen both the USERNAME shell variable and your shell process's user ID change.
root # echo $USERNAME
root
root # USERNAME=JdeBP
JdeBP %
Further reading
- Paul Falstad et al. (2015-12-02). "Parameters Set By The Shell". Z Shell Manual. 5.2.
answered Nov 22 at 15:47
JdeBP
31.8k467148
Running as a superuser I am able to change the variable. Thank you
– Riccardo Persiani
Nov 22 at 15:54
2
@RiccardoPersiani Ummm... switching to root is not a "solution". Why do you need to change the value of this variable?
– Kusalananda
Nov 22 at 16:10
I agree. However, I also can change it, simply switching from zsh to bash.
– Riccardo Persiani
Nov 22 at 16:34
2
Note that there can be more than one user name for a user id,zshreports the one returned bygetpwuid()so an arbitrary one (one could argue it should uselogname()instead). Changing$USERNAMEdoes asetuid(), but alsosetgid()/setgroups()with the groups mentioned in the user database as when you log in as that user name, that's different from setting$UIDor$EUIDfor instance. So by doing aUSERNAME=$USERNAMEyou might very well change the list of groups of the process if there are several usernames for the current uid with different group membership.
– Stéphane Chazelas
Nov 22 at 17:50
add a comment |
up vote
12
down vote
accepted
up vote
12
down vote
accepted
The USERNAME shell variable is special in the Z shell.
It is always the account name of the user ID of the shell process.
You won't observe the behaviour that you observed in the Almquist, Watanabe, Korn, or Bourne Again shells. This variable is just an ordinary shell variable, that starts out unset, as far as they are concerned. Here's the 93 Korn shell, for example:
$ echo $USERNAME
$ USERNAME=wibble
$ echo $USERNAME
wibble
$
In the Z shell it starts out as the account name of the UID of the shell process. An attempt to set it will attempt to change that UID. This of course fails if you are not the superuser and leaves the variable back as it was before.
If you had run the Z shell as the superuser, however, you would have seen both the USERNAME shell variable and your shell process's user ID change.
root # echo $USERNAME
root
root # USERNAME=JdeBP
JdeBP %
Further reading
- Paul Falstad et al. (2015-12-02). "Parameters Set By The Shell". Z Shell Manual. 5.2.
answered Nov 22 at 15:47
JdeBP
31.8k467148
The USERNAME shell variable is special in the Z shell.
It is always the account name of the user ID of the shell process.
You won't observe the behaviour that you observed in the Almquist, Watanabe, Korn, or Bourne Again shells. This variable is just an ordinary shell variable, that starts out unset, as far as they are concerned. Here's the 93 Korn shell, for example:
$ echo $USERNAME
$ USERNAME=wibble
$ echo $USERNAME
wibble
$
In the Z shell it starts out as the account name of the UID of the shell process. An attempt to set it will attempt to change that UID. This of course fails if you are not the superuser and leaves the variable back as it was before.
If you had run the Z shell as the superuser, however, you would have seen both the USERNAME shell variable and your shell process's user ID change.
root # echo $USERNAME
root
root # USERNAME=JdeBP
JdeBP %
Further reading
- Paul Falstad et al. (2015-12-02). "Parameters Set By The Shell". Z Shell Manual. 5.2.
answered Nov 22 at 15:47
JdeBP
31.8k467148
answered Nov 22 at 15:47
JdeBP
31.8k467148
answered Nov 22 at 15:47
JdeBP
31.8k467148
answered Nov 22 at 15:47
JdeBP
31.8k467148
31.8k467148
Running as a superuser I am able to change the variable. Thank you
– Riccardo Persiani
Nov 22 at 15:54
2
@RiccardoPersiani Ummm... switching to root is not a "solution". Why do you need to change the value of this variable?
– Kusalananda
Nov 22 at 16:10
I agree. However, I also can change it, simply switching from zsh to bash.
– Riccardo Persiani
Nov 22 at 16:34
2
Note that there can be more than one user name for a user id,zshreports the one returned bygetpwuid()so an arbitrary one (one could argue it should uselogname()instead). Changing$USERNAMEdoes asetuid(), but alsosetgid()/setgroups()with the groups mentioned in the user database as when you log in as that user name, that's different from setting$UIDor$EUIDfor instance. So by doing aUSERNAME=$USERNAMEyou might very well change the list of groups of the process if there are several usernames for the current uid with different group membership.
– Stéphane Chazelas
Nov 22 at 17:50
add a comment |
Running as a superuser I am able to change the variable. Thank you
– Riccardo Persiani
Nov 22 at 15:54
2
@RiccardoPersiani Ummm... switching to root is not a "solution". Why do you need to change the value of this variable?
– Kusalananda
Nov 22 at 16:10
I agree. However, I also can change it, simply switching from zsh to bash.
– Riccardo Persiani
Nov 22 at 16:34
2
Note that there can be more than one user name for a user id,zshreports the one returned bygetpwuid()so an arbitrary one (one could argue it should uselogname()instead). Changing$USERNAMEdoes asetuid(), but alsosetgid()/setgroups()with the groups mentioned in the user database as when you log in as that user name, that's different from setting$UIDor$EUIDfor instance. So by doing aUSERNAME=$USERNAMEyou might very well change the list of groups of the process if there are several usernames for the current uid with different group membership.
– Stéphane Chazelas
Nov 22 at 17:50
Running as a superuser I am able to change the variable. Thank you
– Riccardo Persiani
Nov 22 at 15:54
Running as a superuser I am able to change the variable. Thank you
– Riccardo Persiani
Nov 22 at 15:54
2
2
@RiccardoPersiani Ummm... switching to root is not a "solution". Why do you need to change the value of this variable?
– Kusalananda
Nov 22 at 16:10
@RiccardoPersiani Ummm... switching to root is not a "solution". Why do you need to change the value of this variable?
– Kusalananda
Nov 22 at 16:10
I agree. However, I also can change it, simply switching from zsh to bash.
– Riccardo Persiani
Nov 22 at 16:34
I agree. However, I also can change it, simply switching from zsh to bash.
– Riccardo Persiani
Nov 22 at 16:34
2
2
Note that there can be more than one user name for a user id,
zsh reports the one returned by getpwuid() so an arbitrary one (one could argue it should use logname() instead). Changing $USERNAME does a setuid(), but also setgid()/setgroups() with the groups mentioned in the user database as when you log in as that user name, that's different from setting $UID or $EUID for instance. So by doing a USERNAME=$USERNAME you might very well change the list of groups of the process if there are several usernames for the current uid with different group membership.– Stéphane Chazelas
Nov 22 at 17:50
Note that there can be more than one user name for a user id,
zsh reports the one returned by getpwuid() so an arbitrary one (one could argue it should use logname() instead). Changing $USERNAME does a setuid(), but also setgid()/setgroups() with the groups mentioned in the user database as when you log in as that user name, that's different from setting $UID or $EUID for instance. So by doing a USERNAME=$USERNAME you might very well change the list of groups of the process if there are several usernames for the current uid with different group membership.– Stéphane Chazelas
Nov 22 at 17:50
add a comment |
Riccardo Persiani is a new contributor. Be nice, and check out our Code of Conduct.
Riccardo Persiani is a new contributor. Be nice, and check out our Code of Conduct.
Riccardo Persiani is a new contributor. Be nice, and check out our Code of Conduct.
Riccardo Persiani is a new contributor. Be nice, and check out our Code of Conduct.
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This variable is readonly and you can change it by switching user
– Romeo Ninov
Nov 22 at 15:26
The weird thing is I am quite sure that I was able to change it, then I had probably messed up with something..
– Riccardo Persiani
Nov 22 at 15:27
Do you see
readonly USERNAMEordeclare -r USERNAMEanywhere? Either of those would mark a variable as read-only.– telcoM
Nov 22 at 15:29
1
This is not a variable that is set by default on macOS. Are you setting it yourself somewhere?
– Kusalananda
Nov 22 at 15:38
2
what does
typeset -p USERNAMEsay?– mosvy
Nov 22 at 15:38