filesplitter.sh

   1 #!/bin/sh
   2
   3 file="$1"
   4 pieces="$2"
   5
   6 [ -z "$pieces" ] && {
   7         printf "%s file pieces\n" "$0"
   8         printf "splits file into 'pieces' pieces.\n"
   9         exit 1
  10 }
  11
  12 [ -e "$file" ] || {
  13         echo "error: file not exists"
  14         exit 1
  15 }
  16
  17 fs=$(wc -c "$file"| cut -d " " -f 1)
  18
  19 chunksz=$((fs / pieces))
  20 bdone=0
  21 md5=$(md5sum "$file"| cut -d " " -f 1)
  22 f=$(basename "$file")
  23
  24 script=$(printf "%s.assemble.sh" "$file")
  25 echo "#!/bin/sh" > "$script"
  26 echo "rm -f \"$f\"" >> "$script"
  27 for i in `seq $pieces` ; do
  28         of=$(printf "%s.part.%.4d" "$file" "$i")
  29         bytes="$chunksz"
  30         if [ "$i" = "$pieces" ] ; then bytes=$((fs - ((pieces-1)*chunksz) )) ; fi
  31         dd if="$file" of="$of" bs=1 skip="$bdone" count="$bytes" >/dev/null 2>&1
  32         bdone=$((bdone + bytes))
  33         ofs=$(basename "$of")
  34         echo "cat \"$ofs\" >> \"$f\"" >> "$script"
  35         echo created "$of".
  36 done
  37 cat << EOF >> "$script"
  38 test \$(md5sum "$f" | cut -d " " -f 1) = $md5 || {
  39 echo "md5 mismatch!"
  40 exit 1
  41 }
  42 echo "successfully recreated $f"
  43 EOF
  44 chmod +x "$script"
  45 echo "created $script".
  46