Discover what filesystem(s) are on a disk/partition?

[humbletech99]

Is there any really good linux program to definitively tell you what filesystem(s) are on a disk/partitions?

When you do mount /dev/sda1, for example, the mount program detects the filesystem type and then mounts the partition as that filesystem so you can use it. I am looking for a program to just run the check of what filesystem it is without mounting the filesystem. I suspect that "mount" does this detection by looking for signatures in the first by bytes of the partition in order to identify it, so there should be some other program that can do this too, right?

EDIT: as I was typing this, I realized that fdisk and parted must be able to do this and they seem to, although I haven't tried them on any random disks yet. If anyone knows of any other good programs for file system detection, could you pls post them here?
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[frostschutz]

file

# file -s /dev/hda1
/dev/hda1: x86 boot sector, Microsoft Windows XP Bootloader NTLDR

# file -s /dev/sda2
/dev/sda2: Linux rev 1.0 ext3 filesystem data (needs journal recovery) (large files)

# file -s /dev/mapper/vg-ccache
/dev/mapper/vg-ccache: ReiserFS V3.6 block size 4096 (mounted or unclean) num blocks 1048576 r5 hash


EDIT:
fdisk doesn't care about file systems, it just shows partition types which has nothing to do with actual data on that partition.
no idea how parted does things.

[humbletech99]

ah, I didn't realize that file could actually work on partitions as well but this makes sense for unix philosophy of abstracting everything as files...

That's what I thought about fdisk in fact, that it looks at partition type rather than reading the actual filesystem itself, there is no guarantee that they are the same thing...

thanks
_________________
The Human Equation:

value(geeks) > value(mundanes)

[VinzC]

[humbletech99]

question is, does it just look at partition types and print that, or does it actually read the filesystem to determine it's structure?
_________________
The Human Equation:

value(geeks) > value(mundanes)

[VinzC]