Shell Programming and Scripting

#!/bin/sh
while read line
do
     while IFS=":" read a b
     do       
        if [ "$a" == "$line" ];then
          echo $b
        fi
     done < "file1"
done <"file2"

#!/usr/bin/env sh

# @(#) s2       Demonstrate saving file in array, processing based on index.

set -o nounset
echo

debug=":"
debug="echo"

## The shebang using "env" line is designed for portability. For
#  higher security, use:
#
#  #!/bin/sh -

## Use local command version for the commands in this demonstration.

echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version bash

echo

FILE1=${1-data1}
echo " Input file $FILE1:"
cat $FILE1

echo
FILE2=${1-data2}
echo " Input file $FILE2:"
cat $FILE2

echo
echo " Results from processing:"

while IFS=":" read a b
do
  content[$a]="$b"
done <$FILE1

while read a
do
  echo ${content[$a]}
done <$FILE2

exit 0

% ./s2

(Versions displayed with local utility "version")
GNU bash 2.05b.0

 Input file data1:
5:John
4:Michel
9:Rachel
100:George

 Input file data2:
9
100
4
5
5
4
9
100
100

 Results from processing:
Rachel
George
Michel
John
John
Michel
Rachel
George
George

#!/usr/bin/perl

my %lookup;
my $main = pop @ARGV;
while (<>) {
        split /:/;
        $lookup{$_[0]} = $_[1];
}

@ARGV = ($main);
while (<>) {
        chomp;
        exists($lookup{$_}) and print $lookup{$_};
}

$ cat file.1
5:John
4:Michel
9:Rachel
100:George

$ cat file.2
9
100
4
5
5
4
9
100
100

$ l.pl file.1 file.2
Rachel
George
Michel
John
John
Michel
Rachel
George
George

awk 'BEGIN{FS=":"}
FNR==NR{
  array[$1]=$2
  next
}
{ print array[$1] }' file file1