BASH/shell script, blkid fails with newlines in drive labels - bash

Question

I have a BASH/shell script, running on Linux, but it sometimes has a problem getting the drive labels, using blkid.. blkid gets the drive labels nad UUIDs of the given drive.
Example of blkid output:
# blkid /dev/sda1
/dev/sda1: LABEL="Home" UUID="f1e5e82b-1c75-4fd7-8841-6ad766152dcf" TYPE="ext2"
The problem occurs when the drive label has a newline character... I have included the relevant function. The problem seems to be with the eval command.. Can someone help me?
blkid_name_generator() {
#Gather blkid output and filter out required device
if [ ! -f /tmp/blkid.txt ]; then
blkid -c /dev/null > /tmp/blkid.txt
fi
blkid_cleaner &
LABEL=""
LABEL1=""
eval $( cat /tmp/blkid.txt | grep "$#:" | cut --delimiter=" " -f 2- | sed -e 's/ /;/g')
LABEL1=${LABEL//;/ } # akita beta4 fix: remove newlines below
LABEL=`echo $LABEL1 | tr -d '\n'` # akita beta5 fix, remove newlines from drive label
#Generate drive label
[ "$LABEL" = "" ] && ONEDRVLABEL="$#\n \n " || ONEDRVLABEL="${LABEL}\n($#)\n "
echo "${LABEL}" and "${ONEDRVLABEL}"
}
blkid_name_generator /dev/sda1

Answer 1

Here's my bash snippet:
while read curline; do
if [[ ${curline:0:1} == "/" ]]; then
[[ $prevline ]] && echo "$prevline"
prevline="$curline"
else
prevline+="$curline"
fi
done < $INPUTFILE
[[ $prevline ]] && echo "$prevline"
Here's my test file:
/dev/sda1: LABEL="Boot" UUID="fdc5e51d-3da6-4edf-bf07-6397b1765797" TYPE="ext2"
/dev/sda2: LABEL="Root" UUID="f883df24-1b93-46fb-8990-840774c380c4" TYPE="ext4"
/dev/sda3: LABEL="Usr" UUID="ba759de3-e0e4-4603-a324-f11dc25fa784" TYPE="reiserfs"
/dev/sdb1: LABEL="Persis
tents" UUID="50b81ef0-a38b-4677-b9d9-9548b29ce2bb" TYPE="ext4"
/dev/sdc1: LABEL="Tempo
raries" UUID="a649c535-1a8a-4b2b-b0a0-4afbdc60a3bc" TYPE="reiserfs"
/dev/sdd1: LABEL="Usr
Portage" UUID="a228148e-6405-4bbe-990f-df6eaebb1b1d" TYPE="reiserfs"
/dev/sda1: LABEL="Boot" UUID="fdc5e51d-3da6-4edf-bf07-6397b1765797" TYPE="ext2"
/dev/sda2: LABEL="Root" UUID="f883df24-1b93-46fb-8990-840774c380c4" TYPE="ext4"
Here's my test file after processed by the bash snippet:
/dev/sda1: LABEL="Boot" UUID="fdc5e51d-3da6-4edf-bf07-6397b1765797" TYPE="ext2"
/dev/sda2: LABEL="Root" UUID="f883df24-1b93-46fb-8990-840774c380c4" TYPE="ext4"
/dev/sda3: LABEL="Usr" UUID="ba759de3-e0e4-4603-a324-f11dc25fa784" TYPE="reiserfs"
/dev/sdb1: LABEL="Persistents" UUID="50b81ef0-a38b-4677-b9d9-9548b29ce2bb" TYPE="ext4"
/dev/sdc1: LABEL="Temporaries" UUID="a649c535-1a8a-4b2b-b0a0-4afbdc60a3bc" TYPE="reiserfs"
/dev/sdd1: LABEL="UsrPortage" UUID="a228148e-6405-4bbe-990f-df6eaebb1b1d" TYPE="reiserfs"
/dev/sda1: LABEL="Boot" UUID="fdc5e51d-3da6-4edf-bf07-6397b1765797" TYPE="ext2"
/dev/sda2: LABEL="Root" UUID="f883df24-1b93-46fb-8990-840774c380c4" TYPE="ext4"
Hope this helps!

Answer 2

I don't see exactly what your script is intending to do (apart from the missing bits).
Here's what I came up with:
blkid | perl -ne 'print "$1\n" if m/LABEL="(.*?)"/o'
It will show this (on my system):
test^J123
WIN7VIRT
TEMP
Note how the newline in the label is depicted as ^J ? Viewing through a hex encoder shows that it is indeed a two-character combination 0x5e 0x4a
Hope you can get some further with that.
PS: 'proof' that the newline is in fact correctly in the volume label
tune2fs /dev/sdc1 -l
tune2fs 1.41.14 (22-Dec-2010)
Filesystem volume name: test
123
Last mounted on: /media/9868d90c-aede-4e7a-b105-d9312f8b17ab
Filesystem UUID: 9868d90c-aede-4e7a-b105-d9312f8b17ab
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
...
and on block level:
dd if=/dev/sdc1 count=10 | xxd | grep 123
0000470: b105 d931 2f8b 17ab 7465 7374 0a31 3233 ...1/...test.123

Answer 3

Thanks to this question... I could find a solution for another problem. Example (sda2 = ntfs partition):
blkid /dev/sda2
Segmentation Fault (core dump)
Hard to find troubleshooting guide for this issue (ubuntu based OS or any other)
The reason behind is a malformed LABEL in NTFS partition.
(of course, mal-formation we cant see, as newlines ;-)
Solution: Clear LABEL with GParted; then rewrite it or set a new LABEL.