That is relatively easy: the dollar sign "$" represents the line end in regular expressions, hence:

Code:

sed 's/$/ nodev/' /some/file

will append nodev to every line at the end - it substitutes the line end with the text. Since you want only certain lines to be modified you can add a regular expression in front to only affect certain lines:

Code:

sed '/nodev/ ! s/$/ nodev/' /some/file

will append nodev only to lines which don't contain the string already. You probably want to refine this a bit more but the principle should be obvious by now.

PS: checking a filesystems current status with the [icode]mount/icode]command and then modify the mount table accordingly is a dangerous proposition: it could already be changed alredy but not been remounted so far. Whenever you change such a thing always base the decision to apply the change on the thing you are modifying, not something else - in this case on the content of the file /etc/fstab.

Also notice that you said you want to change the end of line. You haven't told us your OS but if it is Linux the /etc/fstab has two columns after where you should place your change, here iis the one from my laptop, for example:

Code:

# cat /etc/fstab
# /etc/fstab: static file system information.
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/dev/mapper/rootvg-rootlv /               ext4    noatime,errors=remount-ro 0       1
# /boot was on /dev/sda1 during installation
UUID=xxxxxxxxxx /boot           ext4    defaults        0       2
/dev/mapper/rootvg-homelv /home           ext4    noatime,defaults        0       2
/dev/mapper/rootvg-optlv /opt            ext4    noatime,defaults        0       2
/dev/mapper/rootvg-swaplv none            swap    sw              0       0

I hope this helps.

bakunin