file system - How to check filesystem (/sdcard) for errors?

I would like to check my /sdcard, and possibly other internal partitions as well, for errors on the file system level.

I am wondering how this could be accomplished.

I am using a Samsung Galaxy Nexus (toro) with Verizon Wireless.

Update:
This device does NOT have an actual SD card and I believe the only way to do it is through: "adb shell" (BEFORE system boots (i.e. inside of recovery mode), this way /sdcard is NOT mounted and it's possible to perform checks on it in read/write mode)

Answer

according to: Android Media Process (high CPU) | alexus' blog:

~ # e2fsck -n /dev/block/platform/omap/omap_hsmmc.0/by-name/userdata

e2fsck 1.41.11 (14-Mar-2010)
/dev/block/platform/omap/omap_hsmmc.0/by-name/userdata: clean, 53630/1875968 files, 1921615/7493115 blocks
~ #