How to tell whether a bash script has root privileges [duplicate]
This question already has an answer here:
How can a script check if it's being run as root?
10 answers
I have a bash script that will only work with root privileges, so I want to test whether the user has them. Other posts (see below) ask and answer how to know whether the user is actually running as root, but not whether the script has root privileges. These posts say to test whether $EUID is 0.
To try this idea in the context of sudo, I wrote a bash script /tmp/a.sh:
#!/bin/bash
echo $EUID
The following two commands were run as a non-root user with sudo privileges on Ubuntu 16.04. If the $EUID suggestion worked in the context of sudo, the second command would have printed 0 instead of a blank line.
$ /tmp/a.sh
1000
$ sudo /tmp/a.sh
$
FYI, an example of the related posts I am referencing is:
How can a script check if it's being run as root?
bash
asked Jan 30 at 18:23
Colin McRaeColin McRae
212
marked as duplicate by Sergiy Kolodyazhnyy bash
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Jan 31 at 0:56
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
add a comment |
This question already has an answer here:
How can a script check if it's being run as root?
10 answers
I have a bash script that will only work with root privileges, so I want to test whether the user has them. Other posts (see below) ask and answer how to know whether the user is actually running as root, but not whether the script has root privileges. These posts say to test whether $EUID is 0.
To try this idea in the context of sudo, I wrote a bash script /tmp/a.sh:
#!/bin/bash
echo $EUID
The following two commands were run as a non-root user with sudo privileges on Ubuntu 16.04. If the $EUID suggestion worked in the context of sudo, the second command would have printed 0 instead of a blank line.
$ /tmp/a.sh
1000
$ sudo /tmp/a.sh
$
FYI, an example of the related posts I am referencing is:
How can a script check if it's being run as root?
bash
asked Jan 30 at 18:23
Colin McRaeColin McRae
212
marked as duplicate by Sergiy Kolodyazhnyy bash
Users with the bash badge can single-handedly close bash questions as duplicates and reopen them as needed.
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Jan 31 at 0:56
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
1
echo $UIDshould work. Or according to David F in the comments of your linked answer you should useecho $(id -u)
– Terrance
Jan 30 at 18:32
Thanks Terrance, that works too. I posted an answer after noticing a fat-finger that causes $EUID and $UID to resolve properly only for non-root users (still a bit of a mystery).
– Colin McRae
Jan 30 at 18:43
There are multiple other solutions to detect script running as root on the question to which you referred, if that's really what you're asking. If you are asking specifically why$EUIDdoesn't work, please edit the question to clarify the title and the body of the question, and we can re-open it
– Sergiy Kolodyazhnyy
Jan 31 at 0:58
add a comment |
This question already has an answer here:
How can a script check if it's being run as root?
10 answers
I have a bash script that will only work with root privileges, so I want to test whether the user has them. Other posts (see below) ask and answer how to know whether the user is actually running as root, but not whether the script has root privileges. These posts say to test whether $EUID is 0.
To try this idea in the context of sudo, I wrote a bash script /tmp/a.sh:
#!/bin/bash
echo $EUID
The following two commands were run as a non-root user with sudo privileges on Ubuntu 16.04. If the $EUID suggestion worked in the context of sudo, the second command would have printed 0 instead of a blank line.
$ /tmp/a.sh
1000
$ sudo /tmp/a.sh
$
FYI, an example of the related posts I am referencing is:
How can a script check if it's being run as root?
bash
asked Jan 30 at 18:23
Colin McRaeColin McRae
212
This question already has an answer here:
How can a script check if it's being run as root?
10 answers
I have a bash script that will only work with root privileges, so I want to test whether the user has them. Other posts (see below) ask and answer how to know whether the user is actually running as root, but not whether the script has root privileges. These posts say to test whether $EUID is 0.
To try this idea in the context of sudo, I wrote a bash script /tmp/a.sh:
#!/bin/bash
echo $EUID
The following two commands were run as a non-root user with sudo privileges on Ubuntu 16.04. If the $EUID suggestion worked in the context of sudo, the second command would have printed 0 instead of a blank line.
$ /tmp/a.sh
1000
$ sudo /tmp/a.sh
$
FYI, an example of the related posts I am referencing is:
How can a script check if it's being run as root?
This question already has an answer here:
How can a script check if it's being run as root?
10 answers
bash
bash
asked Jan 30 at 18:23
Colin McRaeColin McRae
212
asked Jan 30 at 18:23
Colin McRaeColin McRae
212
asked Jan 30 at 18:23
Colin McRaeColin McRae
212
asked Jan 30 at 18:23
Colin McRaeColin McRae
212
asked Jan 30 at 18:23
Colin McRaeColin McRae
212
212
marked as duplicate by Sergiy Kolodyazhnyy bash
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Jan 31 at 0:56
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
marked as duplicate by Sergiy Kolodyazhnyy bash
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Jan 31 at 0:56
This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.
1
echo $UIDshould work. Or according to David F in the comments of your linked answer you should useecho $(id -u)
– Terrance
Jan 30 at 18:32
Thanks Terrance, that works too. I posted an answer after noticing a fat-finger that causes $EUID and $UID to resolve properly only for non-root users (still a bit of a mystery).
– Colin McRae
Jan 30 at 18:43
There are multiple other solutions to detect script running as root on the question to which you referred, if that's really what you're asking. If you are asking specifically why$EUIDdoesn't work, please edit the question to clarify the title and the body of the question, and we can re-open it
– Sergiy Kolodyazhnyy
Jan 31 at 0:58
add a comment |
1
echo $UIDshould work. Or according to David F in the comments of your linked answer you should useecho $(id -u)
– Terrance
Jan 30 at 18:32
Thanks Terrance, that works too. I posted an answer after noticing a fat-finger that causes $EUID and $UID to resolve properly only for non-root users (still a bit of a mystery).
– Colin McRae
Jan 30 at 18:43
There are multiple other solutions to detect script running as root on the question to which you referred, if that's really what you're asking. If you are asking specifically why$EUIDdoesn't work, please edit the question to clarify the title and the body of the question, and we can re-open it
– Sergiy Kolodyazhnyy
Jan 31 at 0:58
1
1
echo $UID should work. Or according to David F in the comments of your linked answer you should use echo $(id -u)– Terrance
Jan 30 at 18:32
echo $UID should work. Or according to David F in the comments of your linked answer you should use echo $(id -u)– Terrance
Jan 30 at 18:32
Thanks Terrance, that works too. I posted an answer after noticing a fat-finger that causes $EUID and $UID to resolve properly only for non-root users (still a bit of a mystery).
– Colin McRae
Jan 30 at 18:43
Thanks Terrance, that works too. I posted an answer after noticing a fat-finger that causes $EUID and $UID to resolve properly only for non-root users (still a bit of a mystery).
– Colin McRae
Jan 30 at 18:43
There are multiple other solutions to detect script running as root on the question to which you referred, if that's really what you're asking. If you are asking specifically why
$EUID doesn't work, please edit the question to clarify the title and the body of the question, and we can re-open it– Sergiy Kolodyazhnyy
Jan 31 at 0:58
There are multiple other solutions to detect script running as root on the question to which you referred, if that's really what you're asking. If you are asking specifically why
$EUID doesn't work, please edit the question to clarify the title and the body of the question, and we can re-open it– Sergiy Kolodyazhnyy
Jan 31 at 0:58
add a comment |
2 Answers
2
active
oldest
votes
The script /tmp/a.sh only works with #!/bin/bash on the first line. When actually running the example I gave, the ! was accidentally omitted and the only user reported was the non-root user as shown in the question.
answered Jan 30 at 18:41
Colin McRaeColin McRae
212
2
Probably because without the shebang, the script was interpreted by your current shell (likelybash) when called withoutsudo, but was interpreted bydash(which doesn't setEUID) when called withsudo
– steeldriver
Jan 30 at 18:49
@steeldriver Confirmed. On my Ubuntu 18.04 virtual machine the script withls -l /proc/$$/exereports the script is run via/bin/dash, however on my other debian-based system root hasbashas login shell and that's what is reported there. Sosudochecks either$SHELLenvironment variable or/etc/passwdor other login system such as LDAP
– Sergiy Kolodyazhnyy
Jan 31 at 1:14
@SergiyKolodyazhnyy it's kind of interesting thatsudoappears to use the login shell specified in the target user's passwd entry even when not explicitly invoked with the-i(or--login) option - I'd never really thought about that before
– steeldriver
Jan 31 at 14:22
@steeldriver Correction: it defaults to/bin/sh. I've repeated the experiment couple times again:/proc/19051/exe -> /bin/dashis reported on both systems, so previous conclusion is mistaken.
– Sergiy Kolodyazhnyy
Feb 1 at 0:34
add a comment |
I use the following in some of my scripts:
#!/bin/bash
if [ "$(id -un)" != "root" ]; then
echo "Need root - sudoing..."
exec sudo "$0" "$@"
fi
# Now we are root
answered Jan 30 at 22:26
RalfRalf
20116
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
The script /tmp/a.sh only works with #!/bin/bash on the first line. When actually running the example I gave, the ! was accidentally omitted and the only user reported was the non-root user as shown in the question.
answered Jan 30 at 18:41
Colin McRaeColin McRae
212
2
Probably because without the shebang, the script was interpreted by your current shell (likelybash) when called withoutsudo, but was interpreted bydash(which doesn't setEUID) when called withsudo
– steeldriver
Jan 30 at 18:49
@steeldriver Confirmed. On my Ubuntu 18.04 virtual machine the script withls -l /proc/$$/exereports the script is run via/bin/dash, however on my other debian-based system root hasbashas login shell and that's what is reported there. Sosudochecks either$SHELLenvironment variable or/etc/passwdor other login system such as LDAP
– Sergiy Kolodyazhnyy
Jan 31 at 1:14
@SergiyKolodyazhnyy it's kind of interesting thatsudoappears to use the login shell specified in the target user's passwd entry even when not explicitly invoked with the-i(or--login) option - I'd never really thought about that before
– steeldriver
Jan 31 at 14:22
@steeldriver Correction: it defaults to/bin/sh. I've repeated the experiment couple times again:/proc/19051/exe -> /bin/dashis reported on both systems, so previous conclusion is mistaken.
– Sergiy Kolodyazhnyy
Feb 1 at 0:34
add a comment |
The script /tmp/a.sh only works with #!/bin/bash on the first line. When actually running the example I gave, the ! was accidentally omitted and the only user reported was the non-root user as shown in the question.
answered Jan 30 at 18:41
Colin McRaeColin McRae
212
2
Probably because without the shebang, the script was interpreted by your current shell (likelybash) when called withoutsudo, but was interpreted bydash(which doesn't setEUID) when called withsudo
– steeldriver
Jan 30 at 18:49
@steeldriver Confirmed. On my Ubuntu 18.04 virtual machine the script withls -l /proc/$$/exereports the script is run via/bin/dash, however on my other debian-based system root hasbashas login shell and that's what is reported there. Sosudochecks either$SHELLenvironment variable or/etc/passwdor other login system such as LDAP
– Sergiy Kolodyazhnyy
Jan 31 at 1:14
@SergiyKolodyazhnyy it's kind of interesting thatsudoappears to use the login shell specified in the target user's passwd entry even when not explicitly invoked with the-i(or--login) option - I'd never really thought about that before
– steeldriver
Jan 31 at 14:22
@steeldriver Correction: it defaults to/bin/sh. I've repeated the experiment couple times again:/proc/19051/exe -> /bin/dashis reported on both systems, so previous conclusion is mistaken.
– Sergiy Kolodyazhnyy
Feb 1 at 0:34
add a comment |
The script /tmp/a.sh only works with #!/bin/bash on the first line. When actually running the example I gave, the ! was accidentally omitted and the only user reported was the non-root user as shown in the question.
answered Jan 30 at 18:41
Colin McRaeColin McRae
212
The script /tmp/a.sh only works with #!/bin/bash on the first line. When actually running the example I gave, the ! was accidentally omitted and the only user reported was the non-root user as shown in the question.
answered Jan 30 at 18:41
Colin McRaeColin McRae
212
answered Jan 30 at 18:41
Colin McRaeColin McRae
212
answered Jan 30 at 18:41
Colin McRaeColin McRae
212
answered Jan 30 at 18:41
Colin McRaeColin McRae
212
212
2
Probably because without the shebang, the script was interpreted by your current shell (likelybash) when called withoutsudo, but was interpreted bydash(which doesn't setEUID) when called withsudo
– steeldriver
Jan 30 at 18:49
@steeldriver Confirmed. On my Ubuntu 18.04 virtual machine the script withls -l /proc/$$/exereports the script is run via/bin/dash, however on my other debian-based system root hasbashas login shell and that's what is reported there. Sosudochecks either$SHELLenvironment variable or/etc/passwdor other login system such as LDAP
– Sergiy Kolodyazhnyy
Jan 31 at 1:14
@SergiyKolodyazhnyy it's kind of interesting thatsudoappears to use the login shell specified in the target user's passwd entry even when not explicitly invoked with the-i(or--login) option - I'd never really thought about that before
– steeldriver
Jan 31 at 14:22
@steeldriver Correction: it defaults to/bin/sh. I've repeated the experiment couple times again:/proc/19051/exe -> /bin/dashis reported on both systems, so previous conclusion is mistaken.
– Sergiy Kolodyazhnyy
Feb 1 at 0:34
add a comment |
2
Probably because without the shebang, the script was interpreted by your current shell (likelybash) when called withoutsudo, but was interpreted bydash(which doesn't setEUID) when called withsudo
– steeldriver
Jan 30 at 18:49
@steeldriver Confirmed. On my Ubuntu 18.04 virtual machine the script withls -l /proc/$$/exereports the script is run via/bin/dash, however on my other debian-based system root hasbashas login shell and that's what is reported there. Sosudochecks either$SHELLenvironment variable or/etc/passwdor other login system such as LDAP
– Sergiy Kolodyazhnyy
Jan 31 at 1:14
@SergiyKolodyazhnyy it's kind of interesting thatsudoappears to use the login shell specified in the target user's passwd entry even when not explicitly invoked with the-i(or--login) option - I'd never really thought about that before
– steeldriver
Jan 31 at 14:22
@steeldriver Correction: it defaults to/bin/sh. I've repeated the experiment couple times again:/proc/19051/exe -> /bin/dashis reported on both systems, so previous conclusion is mistaken.
– Sergiy Kolodyazhnyy
Feb 1 at 0:34
2
2
Probably because without the shebang, the script was interpreted by your current shell (likely
bash) when called without sudo, but was interpreted by dash (which doesn't set EUID) when called with sudo– steeldriver
Jan 30 at 18:49
Probably because without the shebang, the script was interpreted by your current shell (likely
bash) when called without sudo, but was interpreted by dash (which doesn't set EUID) when called with sudo– steeldriver
Jan 30 at 18:49
@steeldriver Confirmed. On my Ubuntu 18.04 virtual machine the script with
ls -l /proc/$$/exe reports the script is run via /bin/dash, however on my other debian-based system root has bash as login shell and that's what is reported there. So sudo checks either $SHELL environment variable or /etc/passwd or other login system such as LDAP– Sergiy Kolodyazhnyy
Jan 31 at 1:14
@steeldriver Confirmed. On my Ubuntu 18.04 virtual machine the script with
ls -l /proc/$$/exe reports the script is run via /bin/dash, however on my other debian-based system root has bash as login shell and that's what is reported there. So sudo checks either $SHELL environment variable or /etc/passwd or other login system such as LDAP– Sergiy Kolodyazhnyy
Jan 31 at 1:14
@SergiyKolodyazhnyy it's kind of interesting that
sudo appears to use the login shell specified in the target user's passwd entry even when not explicitly invoked with the -i (or --login) option - I'd never really thought about that before– steeldriver
Jan 31 at 14:22
@SergiyKolodyazhnyy it's kind of interesting that
sudo appears to use the login shell specified in the target user's passwd entry even when not explicitly invoked with the -i (or --login) option - I'd never really thought about that before– steeldriver
Jan 31 at 14:22
@steeldriver Correction: it defaults to
/bin/sh . I've repeated the experiment couple times again: /proc/19051/exe -> /bin/dash is reported on both systems, so previous conclusion is mistaken.– Sergiy Kolodyazhnyy
Feb 1 at 0:34
@steeldriver Correction: it defaults to
/bin/sh . I've repeated the experiment couple times again: /proc/19051/exe -> /bin/dash is reported on both systems, so previous conclusion is mistaken.– Sergiy Kolodyazhnyy
Feb 1 at 0:34
add a comment |
I use the following in some of my scripts:
#!/bin/bash
if [ "$(id -un)" != "root" ]; then
echo "Need root - sudoing..."
exec sudo "$0" "$@"
fi
# Now we are root
answered Jan 30 at 22:26
RalfRalf
20116
add a comment |
I use the following in some of my scripts:
#!/bin/bash
if [ "$(id -un)" != "root" ]; then
echo "Need root - sudoing..."
exec sudo "$0" "$@"
fi
# Now we are root
answered Jan 30 at 22:26
RalfRalf
20116
add a comment |
I use the following in some of my scripts:
#!/bin/bash
if [ "$(id -un)" != "root" ]; then
echo "Need root - sudoing..."
exec sudo "$0" "$@"
fi
# Now we are root
answered Jan 30 at 22:26
RalfRalf
20116
I use the following in some of my scripts:
#!/bin/bash
if [ "$(id -un)" != "root" ]; then
echo "Need root - sudoing..."
exec sudo "$0" "$@"
fi
# Now we are root
answered Jan 30 at 22:26
RalfRalf
20116
answered Jan 30 at 22:26
RalfRalf
20116
answered Jan 30 at 22:26
RalfRalf
20116
answered Jan 30 at 22:26
RalfRalf
20116
20116
add a comment |
add a comment |
1
echo $UIDshould work. Or according to David F in the comments of your linked answer you should useecho $(id -u)– Terrance
Jan 30 at 18:32
Thanks Terrance, that works too. I posted an answer after noticing a fat-finger that causes $EUID and $UID to resolve properly only for non-root users (still a bit of a mystery).
– Colin McRae
Jan 30 at 18:43
There are multiple other solutions to detect script running as root on the question to which you referred, if that's really what you're asking. If you are asking specifically why
$EUIDdoesn't work, please edit the question to clarify the title and the body of the question, and we can re-open it– Sergiy Kolodyazhnyy
Jan 31 at 0:58