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How to add nodev for /dev/shm partition in Linux using shell script?


 
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# 1  
Old 08-29-2014
How to add nodev for /dev/shm partition in Linux using shell script?

Hi,
Please guide me how to add nodev option for /dev/shm partition.

I am new to scripting and looking to do via command line.

Thanks
Litu
# 2  
Old 08-29-2014
Hi,

To do this from the command line, you will have to use the mount command, it will be something like.

Code:
mount -t tmpfs -o remount,nodev /dev/shm

But this will be OS specific and you will need to do this as the root user.

A good place to start will be;
Code:
cat /etc/fstab

That will give you some information and you should be able to get the rest using;

Code:
man mount

Regards

Dave

Last edited by gull04; 08-29-2014 at 09:56 AM.. Reason: Syntax
# 3  
Old 08-29-2014
Actually, I think that the OP wants to alter /etc/fstab via a shell script to make this change permanent. I had to make a similar change because our security auditors requested it. In my case i had to modify our kickstart file so that "nodev,nosuid,noexec" was added to /dev/shm during the OS installation. What I did was:
Code:
awk ' $2=="/dev/shm" { $4=$4",nodev,nosuid,noexec" ;} 1' < fstab  > fstab.new
cp fstab.new fstab
rm fstab.new

There were other, similiar changes to other file systems. I gave each one it's own paragraph. This makes it easy to modify later. That awk statement is very easy to understand which means that I don't need to waste time explaining code to an auditor who is reviewing my kickstart.
# 4  
Old 08-29-2014
Hi Perderabo,

Inclined to agree with you having had a second look at the original post, the being new to scripting is actually a clue I realise now.

Regards

Dave
# 5  
Old 09-01-2014
Hi Perderabo/ gull04,

Thanks for the response. I will try this out and update this thread. I am using RHEL 5 and RHEL 6 Version.

Hopefully, gu1104's solution will work. currently we are avoiding use of awk command as we have huge no (in thousands)of servers and doing it so via scripting may impact performance.
# 6  
Old 09-01-2014
Hi Litu1988,

If your infratructure will stand the scripting, that is the way to go - hand editing "(in thousands)" of /etc/fstab files will be a real pain.

I'd bite the bullet and work on the script if you can.

Regards

Dave
# 7  
Old 09-01-2014
Hi Gull04,

I tried your way. But changes were not reflected in /etc/fstab or /etc/mtab file.

do i need to restart the server for changes to reflect in the file ?

I have fstab in below format

Code:
tmpfs                   /dev/shm                tmpfs   defaults        0 0

expected result after command executed.
Code:
tmpfs                   /dev/shm                tmpfs   defaults,nodev        0 0


Kindly guide.

Last edited by Litu1988; 09-01-2014 at 07:25 AM.. Reason: code tag added

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