Replacing /bin/bash with /bin/false in /etc/passwd file

Question

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?

Solution 1

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.

Solution 2

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 )

Comments

[Stepo]

mv /bin/bash /tmp/bin/false

[chepner]

@Stepo That just makes /bin/bash unavailable to everyone.

[Stepo]

ah gosh, I see. you're right!

[Admin]

chsh says command not found!! i am using solaris

[0xC0000022L]

@user1212207: on my SunOS 5.8 SUNW,UltraAX-i2 ther is a usermod. And it even supports -s. I stand by my answer.

[Admin]

yeah usermod works fine!!! and solved my problem