Shell Programming and Scripting

col1     col2    col3
b100:07-24-2018:test1
b102:04-24-2017:test2
b103:04-24-2017:test3
b104:04-24-2017:test3

col4          col5
b100:name1@email.com
b102:name2@email.com
b103:name3@email.com

#read first file
cat file1.txt | while IFS=':' read col1 col2 col3;

do

#check string in second file

if grep -w $col1 file2.txt
then
  echo "match string"
  echo $col1,$col2,$col3,$col5
else
  echo "not match string" $userid
fi
done

awk -F: 'NR==FNR {T[$1]=$2; next} {print $0, T[$1]}' OFS=: file2 file1
col1     col2    col3:
b100:07-24-2018:test1:name1@email.com
b102:04-24-2017:test2:name2@email.com
b103:04-24-2017:test3:name3@email.com
b104:04-24-2017:test3:

while IFS=': ' read col1 col2 col3
  do    if      TMP=$(grep -w $col1 file2)
          then  echo "match string"
                echo $col1,$col2,$col3,${TMP#*:}
          else  echo "not match string" $userid
        fi
  done < file1

#!/bin/bash
# bash version 4 required

# associative array
declare -A AR

# read file into array, key is col1
while IFS=':' read col1 col2
do
  AR[$col1]=$col2
done < file2.txt

# lookup the key col1 in array
while IFS=':' read col1 col2 col3
do
  lookup=${AR[$col1]}
  if [ -n "$lookup" ]
  then
    echo "$col1,$col2,$col3,$lookup"
  else
    echo "no match: $col1"
  fi
done < file1.txt