Disks and filesystems

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badblocks -v- s /dev/sdb >badblocks.log
Check a device for bad blocks
fdisk /dev/sdb
Manage disk partitions
df -h
Show filesystem block usage in human friendly format
df -i
Show filesystem inode usage
ls -i <file>
Show inode of <file>
rm -i <file>
Remove a file by its inode
mount -t <fstype> -o <options> <devicefile> <mountpoint>
Mount a filesystem (fstype and options can be omitted often)
mount -o loop /path/to/my-iso-image.iso /mnt/iso
Mount an .iso file


The graphical utility Disks has a benchmark option.

dd if=/dev/zero of=./test.tmp bs=1G count=1 oflag=dsync;rm -f ./test.tmp
Check plain write speed
dd if=/dev/zero of=./test.tmp bs=512 count=1000 oflag=dsync;rm -f ./test.tmp
Latency test

On an empty disk you can do:

dd if=/dev/zero of=/dev/sdb bs=8k count=10k
Test disk write speed if no filesystem exists


The unix black hole. Write always succeeds with no effect at all.
Provides an unlimited amount of null characters (ASCII 0). Can be used for cleaning disks or benchmarking (see #Performance)
Writing to /dev/zero is the same as writing to /dev/null