#!/bin/bash
# Purpose:
# A crude test of file system integrity.
# Developed it to detect faulty CDs.

# Method:
# Crawl the file system, starting in the current directory
# and copy each file to /dev/null. Except in verbose mode
# only I/O error messages will be shown on console.

if [ x$1 = x-h ] || [ x$2 = x-h ] || [ x$3 = x-h ] || [ x$4 = x-h ]
  then echo "   Usage:  nullcheck [ -a -d -h -v ]"
       echo "   -a include hidden files and directories"
       echo "   -d dereference symlinks (to be implimented)"
       echo "   -h print this message and exit"
       echo "   -v verbose: explain what is being done (for debugging only)"
       echo
       exit 0
fi

# Test for command line switches
if [ x$1 = x-v ] || [ x$2 = x-v ] || [ x$3 = x-v ] 
  then verbose=1
  else verbose=0
fi
export verbose

if [ x$1 = x-a ] || [ x$2 = x-a ] || [ x$3 = x-a ]
  then list ()
       { 
        ls -A 
        }
  else list ()
       { 
         ls
       }
fi

if [ x$1 = x-d ] || [ x$2 = x-d ] || [ x$3 = x-d ]
  then deref=1
  else deref=0
fi
export deref

check ()
{
for i in $(list)
  do 
    if ( ! test -L "$i" ) || ( test $deref = 1 )
      then
        if test -d "$i";
          then 
            if [ $verbose = 1 ]
              then echo "entering directory: $PWD/$i"
            fi
            cd "$i"
            check $*
            if [ $verbose = 1 ]
              then echo "leaving directory: $PWD"
            fi
            cd ..
          else
            if [ $verbose = 1 ]
              then echo "testing file: $PWD/$i"
            fi
            cp "$i" /dev/null;
        fi
    fi
  done
}
check