sed usage

[Achilles_2]

Hi all,

I am writing a setup srcipt which want to replace one line of the file /etc/passwd

root::0:3::/:/sbin/sh
daemon:*:1:5::/:/sbin/sh
bin:*:2:2::/usr/bin:/sbin/sh
sys:*:3:3::/:
adm:*:4:4::/var/adm:/sbin/sh
uucp:*:5:3::/var/spool/uucppublic:/usr/lbin/uucp/uucico
lp:*:9:7::/var/spool/lp:/sbin/sh
nuucp:*:11:11::/var/spool/uucppublic:/usr/lbin/uucp/uucico
hpdb:*:27:1:ALLBASE:/:/sbin/sh
nobody:*:-2:-2::/:
www:*:30:1::/:
smbnull:*:101:101:DO NOT USE OR DELETE - needed by Samba:/home/smbnull:/sbin/sh

to root::0:3::/.root:/sbin/ksh, my idea is to use sed

grep root /etc/passwd | sed -e 's/"/"/"/.root"/' -e 's/"/sbin/sh"/"/sbin/ksh"/'
but I find that the character / is the special.

Do anyone has an idea? Thanks

[Arunvijai_4]

You can use \/ instead.

-Arun

[Pete Randall]

You're trying to change root's shell to the korn shell? This is NOT a good idea. When you need to boot into single user mode, the korn shell is not going to be available, because /usr is not mounted. And, unless you managed to put it there, which is unlikely because it's dynamically rather than staticaly linked, ksh is not in /sbin, anyway.

I would rethink this whole proposal if I were you.


Pete

[Muthukumar_5]

If you want to change /etc/passwd file then use passwd command first. Leave root account's shell as /sbin/sh. It is the only one account going to be used in single user mode.

If you want to play manually then,

# cp -p /etc/passwd /etc/passwd.bak
# passwd -e /sbin/ksh root

It will change /sbin/sh to /sbin/ksh

hth.

[Arunvijai_4]

there is no /sbin/ksh available on HP-UX. Double check before doing anything,

# ls /sbin/ksh (11.11 and 11.23)
/sbin/ksh not found

-Arun

[Stephen Keane]

As Pete says you probably want to rethink what you are trying to do, but for future reference you can use another delimiter with sed if you want.

e.g.

# sed -e 's|before|after|g' file

uses the pipe symbol '|' as the delimiter.

so in your case ...

grep "^root:" /etc/passwd | sed -e 's|/sbin/sh|/sbin/ksh|'

[James R. Ferguson]

Hi:

Pete is correct. Unless you only want to boot your system one last time, do *NOT* change root's shell! It must remain '/sbin/sh' as he noted. On HP-UX, 'sh' is the POSIX shell which is a superset of the Korn88 shell -- which is all you get with '/usr/bin/ksh'.

Regards!

...JRF...

[Muthukumar_5]

For sed practice you can try as,

# sed -e '/root/s/sh/ksh/g' /etc/passwd

It won't update in /etc/passwd

You can negate / with \ or else s## instead of s// or s%%.

# echo "root::0:3::/.root:/sbin/sh" | sed -e '/root/s%/sbin/sh%/sbin/ksh%'
root::0:3::/.root:/sbin/ksh
# echo "root::0:3::/.root:/sbin/sh" | sed -e '/root/s#/sbin/sh#/sbin/ksh#'
root::0:3::/.root:/sbin/ksh
# echo "root::0:3::/.root:/sbin/sh" | sed -e '/root/s/\/sbin\/sh/\/sbin\/ksh/'
root::0:3::/.root:/sbin/ksh
# echo "root::0:3::/.root:/sbin/sh" | sed -e '/root/s|/sbin/sh|/sbin/ksh|'
root::0:3::/.root:/sbin/ksh

hth.

[John M.]

How about using /usr/sbin/logins command to generate list of users then use that list as input to /usr/sbin/usermod command for each users in for loop?
It fails for users that are logged on, but can be scheduled to run offshift.

[Stuart Abramson]

There is a lot of good advice about changing the root password shell above. Take it.

There is no difference between ksh and sh on hpux anymore, so NO reason to make this change anyway.