Bashscripts.org

#!/bin/bash
# take the input file as argument 1
file=$1
# Set the seperator symbol to a new line
IFS="
"
# Some incrementors, $a is set to -1 to compensate for the first occurance of "zip"
a=-1
b=0
# loop throu the text file
for i in $(cat $file); do
   # If we find "zip" then we create another element in our pseudo-multidimensional array
   echo $i | grep "zip" &> /dev/null
   if [ $? -eq 0 ]; then
      ((a++))
      b=0
   fi
   # Add that line to the array
   eval "array$a[$b]=\"$i\""
   ((b++))
done

# Start looping throu the multidimensional array
b=0
while [ $b -le $a ]; do
   name="array$b"
   # Get the length of the current "zip code array element"
   len=$(eval "echo \${#$name[@]}")
   # clear previous values, in case city is missing.
   unset zip city
   for i in $(seq 1 $len); do
      ((i--))
      # Retrieve the value
      value=$(eval "echo \${$name[$i]}")
      # Check if the value is something to print, or if its informational
      case $value in
         # This will react to any combination of cases for the word "zip"
         [Zz][Ii][Pp]*) zip=$(echo $value | cut -d':' -f2) ;;
         # This will react to any combination of cases for the word "city"
         [Cc][Ii][Tt][Yy]*) city=$(echo $value | cut -d':' -f2) ;;
         # if none of the above is found it's time to echo the output
         *) echo -e "$value\t$city\t$zip" ;;
      esac
   done
   ((b++))
done

Usage: ./script.sh file-containing-lines.txt

sajko@hanna:~> cat test.txt
zip:12345
city:some city
1234    main street
1235    main street
1242    main street
1245    main street
zip:2345
city:some city2
1257    main street
1259    main street
1260    main street
1266    main street
sajko@hanna:~> sh test.sh test.txt
1234    main street     some city       12345
1235    main street     some city       12345
1242    main street     some city       12345
1245    main street     some city       12345
1257    main street     some city2      2345
1259    main street     some city2      2345
1260    main street     some city2      2345
1266    main street     some city2      2345