FSCK Utility is for checking and repairing the files system inconsistencies, It has 5 phases 

Phase 1: Check Blocks and SIZES - checks inodes for inconsistencies
Phase 2: Check Path-Names - checks directory inode consistencies
Phase 3: Check Connectivity - checks that all directories are connected to the file system
Phase 4: Check Reference COUNTS - compares link count information from Phases 2 & 3, correcting discrepancies
Phase 5: Check Cylinder Groups - checks free blocks and the used inode maps for consistency
Phase 6: Salvage Cylinder Groups - UPDATE the tables to reflect any CHANGES made in earlier passes

FSCK Utility is for checking and repairing the files system inconsistencies, It has 5 phases 

Phase 1: Check Blocks and Sizes - checks inodes for inconsistencies
Phase 2: Check Path-Names - checks directory inode consistencies
Phase 3: Check Connectivity - checks that all directories are connected to the file system
Phase 4: Check Reference Counts - compares link count information from Phases 2 & 3, correcting discrepancies
Phase 5: Check Cylinder Groups - checks free blocks and the used inode maps for consistency
Phase 6: Salvage Cylinder Groups - update the tables to reflect any changes made in earlier passes