Linux/Snippets

File system & drives

List directory sizes

clear;   for each in $(ls) ; do du -hs "$each" ; done

Measure execution time

START=$(date +%s.%N)
command
END=$(date +%s.%N)
DIFF=$(echo "$END - $START" | bc)

find file with content

grep -iR "$PATTERN" *

find top 10 biggest files

du -hsx * | sort -rh | head -10

clear file content

echo "" > filename
or
for i in *; do cat /dev/null > $i; done

show hdd power states

sudo hdparm -C /dev/sd?

show SMART data

sudo smartctl -a /dev/sd?

check for bad sectors

fsck.ext4 -cDfty -C 0 /dev/sdxx

Manual SSD Trim

sudo fstrim -v /   

Cron SSD Trim

/etc/scripts/fstrim.sh:

#!/bin/sh
#
echo `date +"%d %b %H:%M:%S"` | tr -d '\n' >> /var/log/fstrim
/sbin/fstrim -v / >> /var/log/fstrim

/etc/cron.d/fstrim:

#
0 * * * * root /etc/scripts/fstrim.sh

kernel

remove old kernels

dpkg -l linux-* | awk '/^ii/{ print $2}' | grep -v -e `uname -r | cut -f1,2 -d"-"` | grep -e [0-9] | xargs sudo apt-get --dry-run remove