[CentOS] Need fstab-decode for CentOS 8

Mon Feb 28 07:22:23 UTC 2022
centos at niob.at <centos at niob.at>

Am 28.02.22 um 05:45 schrieb Robert Nichols:
> On 2/27/22 12:26 PM, centos at niob.at wrote:
>> Am 27.02.22 um 04:33 schrieb Robert Nichols:
>>> Does anything for CentOS 8 provide the function of the fstab-decode 
>>> utility?
>>> Entries in /proc/mounts and /etc/fstab can have escape sequences for 
>>> certain special characters, and I need to decode that. 
>> Preface: Never heard of fstab-decode before. Researching the command 
>> made me really wonder why it was invented. Especially since I have 
>> never seen an /etc/fstab with "escape sequences" or "special 
>> characters" since at least 1990 (If I am wrong: Please show me such a 
>> fstab file).
>> So why not just use:
>>      umount $(awk '$3 == "vfat" {print $2}' /etc/fstab)
>> instead of the seemingly canonical use of fstab-decode
>>      fstab-decode umount $(awk '$3 == "vfat" { print $2 }' /etc/fstab)
> Those samples break if the mount point directory name contains spaces, 
> tabs, or whatever other characters I don't know about that also get 
> represented by escape sequences. I'm not actually using it with 
> /etc/fstab, but with /proc/mounts which uses the same convention. I 
> can control /etc/fstab and avoid the problem, but I cannot control how 
> some auto-mounted foreign filesystem might be named. I have a script 
> that needs to be robust in the face of such names.
Get creative! Unix administration is a creative job. Having said this:

Using white space within mount points is asking for trouble anyway. If 
you really want this in the most generic way, then do the unquoting with 
something like this:

     awk '$3 == "vfat" {print $2}' /etc/fstab | perl -pl000 -e 
's/\\([0-7]{3})/chr(oct($1))/eg' | xargs -0 -n 1 -r umount

This seems to be the unixy way to do this.

If you really need the fstab-decode program put this in a script (if you 
want to be able to use commands with arguments you may choose to remove 
the double quotes in the argument to xargs):

	# a simple fstab-decode implementation....


	while [ -n "$1" ] ; do
         	echo -E "$1"
	done | perl -pl000 -e 's/\\([0-7]{3})/chr(oct($1))/eg;' | xargs -0 -n 1 -r "$CMD"