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I am writing a program to disable users from a system, i want to replace /bin/bash to /bin/false.

Example

xxx:x:1:22:xx:/export/home/xx:**/bin/bash**

replace to

xxx:x:1:22:xx:/export/home/xx:**/bin/false**

I want do with using bash script.

I know one way to do this is using sed. But i am not good at regular expressions.

Can any one help?

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migrated from stackoverflow.com Feb 27 '13 at 20:02

This question came from our site for professional and enthusiast programmers.

    
mv /bin/bash /tmp/bin/false – Stepo Feb 27 '13 at 17:07
5  
@Stepo That just makes /bin/bash unavailable to everyone. – chepner Feb 27 '13 at 17:08
    
ah gosh, I see. you're right! – Stepo Feb 27 '13 at 17:10
up vote 8 down vote accepted

Well you don't do it at all with sed or regular expressions. What you do is to use the program chsh to change the shell of a user.

chsh -s /bin/false username

alternatively:

usermod -s /bin/false username

If you wanted to replace it with an actual shell you'd also have to make sure that it is listed in /etc/shells.

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chsh says command not found!! i am using solaris – user1212207 Feb 27 '13 at 17:13
    
@user1212207: on my SunOS 5.8 SUNW,UltraAX-i2 ther is a usermod. And it even supports -s. I stand by my answer. – 0xC0000022L Feb 27 '13 at 17:24
    
yeah usermod works fine!!! and solved my problem – user1212207 Feb 27 '13 at 17:36
    
Thanks for the help – user1212207 Feb 27 '13 at 17:37

Please be aware that chsh is not always available! in alpine Linux for example or embeded systems using busybox ..

Simple inline sed command :

sed -i '/www-data/s/false/sh/g' /etc/passwd

(This example changes shell from /bin/false to /bin/sh for user www-data )

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