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-1

When I run

user@hostname:~$ su -- root -z

I get

bash: -z: invalid option

Usage:  bash [GNU long option] [option] ...

...

The above is the behavior I expect.

When I run

user@hostname:~$ su -l -- root -z

I get

-su: -z: invalid option

Usage:  -su [GNU long option] [option] ...

...

I use the invalid option -z only to demonstrate which command is parsing the option.

This behavior irks me to no end. su continued searching for options after I declared end of options. Am I missing something, is this a bug or just horrible design?

su gnu

share|improve this question

edited 52 mins ago

Harold Fischer

asked 1 hour ago

Harold FischerHarold Fischer

688415

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I am confused.... Which OS has a -z switch for sudo or su? It looks like you might be trying to do either su - root or sudo -i. It's never sudo su. The commands are mutually exclusive.
  
  – Christopher
  57 mins ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  -z is not an option for su or bash. It is intentional. I used a fake option to demonstrate which command was parsing the fake option I gave it.
  
  – Harold Fischer
  56 mins ago
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Was sudo su supposed to demonstrate something in particular? Ref @Christopher's question
  
  – Seamus
  43 mins ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Seamus No I was using sudo for debugging so I wouldn't have to enter a password for root every time I tested it. I tested without sudo and the behavior is the same. I can see how it completely diluted the question and made it confusing
  
  – Harold Fischer
  42 mins ago
  
  
  

  
  
  
  

add a comment | 

-1

When I run

user@hostname:~$ su -- root -z

I get

bash: -z: invalid option

Usage:  bash [GNU long option] [option] ...

...

The above is the behavior I expect.

When I run

user@hostname:~$ su -l -- root -z

I get

-su: -z: invalid option

Usage:  -su [GNU long option] [option] ...

...

I use the invalid option -z only to demonstrate which command is parsing the option.

This behavior irks me to no end. su continued searching for options after I declared end of options. Am I missing something, is this a bug or just horrible design?

su gnu

share|improve this question

edited 52 mins ago

Harold Fischer

asked 1 hour ago

Harold FischerHarold Fischer

688415

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I am confused.... Which OS has a -z switch for sudo or su? It looks like you might be trying to do either su - root or sudo -i. It's never sudo su. The commands are mutually exclusive.
  
  – Christopher
  57 mins ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  -z is not an option for su or bash. It is intentional. I used a fake option to demonstrate which command was parsing the fake option I gave it.
  
  – Harold Fischer
  56 mins ago
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Was sudo su supposed to demonstrate something in particular? Ref @Christopher's question
  
  – Seamus
  43 mins ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Seamus No I was using sudo for debugging so I wouldn't have to enter a password for root every time I tested it. I tested without sudo and the behavior is the same. I can see how it completely diluted the question and made it confusing
  
  – Harold Fischer
  42 mins ago
  
  
  

  
  
  
  

add a comment | 

When I run

user@hostname:~$ su -- root -z

I get

bash: -z: invalid option

Usage:  bash [GNU long option] [option] ...

...

The above is the behavior I expect.

When I run

user@hostname:~$ su -l -- root -z

I get

-su: -z: invalid option

Usage:  -su [GNU long option] [option] ...

...

I use the invalid option -z only to demonstrate which command is parsing the option.

This behavior irks me to no end. su continued searching for options after I declared end of options. Am I missing something, is this a bug or just horrible design?

su gnu

share|improve this question

edited 52 mins ago

Harold Fischer

asked 1 hour ago

Harold FischerHarold Fischer

688415

user@hostname:~$ su -- root -z

bash: -z: invalid option

Usage:  bash [GNU long option] [option] ...

...

user@hostname:~$ su -l -- root -z

-su: -z: invalid option

Usage:  -su [GNU long option] [option] ...

...

share|improve this question

edited 52 mins ago

Harold Fischer

asked 1 hour ago

Harold FischerHarold Fischer

688415

share|improve this question

edited 52 mins ago

Harold Fischer

asked 1 hour ago

Harold FischerHarold Fischer

688415

asked 1 hour ago

Harold FischerHarold Fischer

688415

asked 1 hour ago

Harold FischerHarold Fischer

688415

1 Answer
1

active

oldest

votes

2

-su: -z: invalid option

Usage:  -su [GNU long option] [option] ...

...

This is the error output from Bash, not from su. If you'd continued to quote, the very next line mentions a script file, for example, and later on the --rcfile option, which clearly doesn't belong to su. You could also compare to the output of su -z, which will be a different error.

If you run

su -l -- root --version

you'll see that the argument is passed along and it's Bash that reports its version.

Bash is reporting itself as -su (note the -) because that's what is in its zeroth argument when su invokes it as a login shell, not because it is su itself (or even -su).

---

Note that the su manual does actually state that:

You can use the -- argument to separate su options from the arguments
supplied to the shell.

which is what is happening here: the argument is passed along to the shell. If you'd left the -- out, you'd get the su error output

su: invalid option -- 'z'

Usage: su [options] [LOGIN]

...

instead.

share|improve this answer

answered 41 mins ago

Michael HomerMichael Homer

52.5k9144181

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for taking the time to point out my silly mistake. When I run su -- root -, bash complains it cannot set the the terminal process group. Shouldn't bashjust treat the - as end of options and start up the shell like the - isn't there?
  
  – Harold Fischer
  14 mins ago
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If you provide shell arguments su doesn't give it a controlling TTY (try su -- root -x). I don't quite understand that choice, but it is consistent with su -c 'bash' so I suppose that's part of it.
  
  – Michael Homer
  5 mins ago
  

  
  
  
  

add a comment | 

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2

-su: -z: invalid option

Usage:  -su [GNU long option] [option] ...

...

This is the error output from Bash, not from su. If you'd continued to quote, the very next line mentions a script file, for example, and later on the --rcfile option, which clearly doesn't belong to su. You could also compare to the output of su -z, which will be a different error.

If you run

su -l -- root --version

you'll see that the argument is passed along and it's Bash that reports its version.

Bash is reporting itself as -su (note the -) because that's what is in its zeroth argument when su invokes it as a login shell, not because it is su itself (or even -su).

---

Note that the su manual does actually state that:

You can use the -- argument to separate su options from the arguments
supplied to the shell.

which is what is happening here: the argument is passed along to the shell. If you'd left the -- out, you'd get the su error output

su: invalid option -- 'z'

Usage: su [options] [LOGIN]

...

instead.

share|improve this answer

answered 41 mins ago

Michael HomerMichael Homer

52.5k9144181

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for taking the time to point out my silly mistake. When I run su -- root -, bash complains it cannot set the the terminal process group. Shouldn't bashjust treat the - as end of options and start up the shell like the - isn't there?
  
  – Harold Fischer
  14 mins ago
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If you provide shell arguments su doesn't give it a controlling TTY (try su -- root -x). I don't quite understand that choice, but it is consistent with su -c 'bash' so I suppose that's part of it.
  
  – Michael Homer
  5 mins ago
  

  
  
  
  

add a comment | 

2

-su: -z: invalid option

Usage:  -su [GNU long option] [option] ...

...

This is the error output from Bash, not from su. If you'd continued to quote, the very next line mentions a script file, for example, and later on the --rcfile option, which clearly doesn't belong to su. You could also compare to the output of su -z, which will be a different error.

If you run

su -l -- root --version

you'll see that the argument is passed along and it's Bash that reports its version.

Bash is reporting itself as -su (note the -) because that's what is in its zeroth argument when su invokes it as a login shell, not because it is su itself (or even -su).

---

Note that the su manual does actually state that:

You can use the -- argument to separate su options from the arguments
supplied to the shell.

which is what is happening here: the argument is passed along to the shell. If you'd left the -- out, you'd get the su error output

su: invalid option -- 'z'

Usage: su [options] [LOGIN]

...

instead.

share|improve this answer

answered 41 mins ago

Michael HomerMichael Homer

52.5k9144181

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thanks for taking the time to point out my silly mistake. When I run su -- root -, bash complains it cannot set the the terminal process group. Shouldn't bashjust treat the - as end of options and start up the shell like the - isn't there?
  
  – Harold Fischer
  14 mins ago
  
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  If you provide shell arguments su doesn't give it a controlling TTY (try su -- root -x). I don't quite understand that choice, but it is consistent with su -c 'bash' so I suppose that's part of it.
  
  – Michael Homer
  5 mins ago
  

  
  
  
  

add a comment | 

-su: -z: invalid option

Usage:  -su [GNU long option] [option] ...

...

This is the error output from Bash, not from su. If you'd continued to quote, the very next line mentions a script file, for example, and later on the --rcfile option, which clearly doesn't belong to su. You could also compare to the output of su -z, which will be a different error.

If you run

su -l -- root --version

you'll see that the argument is passed along and it's Bash that reports its version.

Bash is reporting itself as -su (note the -) because that's what is in its zeroth argument when su invokes it as a login shell, not because it is su itself (or even -su).

---

Note that the su manual does actually state that:

You can use the -- argument to separate su options from the arguments
supplied to the shell.

which is what is happening here: the argument is passed along to the shell. If you'd left the -- out, you'd get the su error output

su: invalid option -- 'z'

Usage: su [options] [LOGIN]

...

instead.

share|improve this answer

answered 41 mins ago

Michael HomerMichael Homer

52.5k9144181

su -l -- root --version

su: invalid option -- 'z'

Usage: su [options] [LOGIN]

...

share|improve this answer

answered 41 mins ago

Michael HomerMichael Homer

52.5k9144181

answered 41 mins ago

Michael HomerMichael Homer

52.5k9144181

answered 41 mins ago

Michael HomerMichael Homer

52.5k9144181