Shell Programming and Scripting

#!/bin/bash
# Shell script utility to read a file line line.
# Once line is read it can be process in processLine() function
# You can call script as follows, to read myfile.txt:
# ./readline myfile.txt
# Following example will read line from standard input device aka keyboard:
# ./readline

# User define Function (UDF)
processLine(){
  line="$@" # get all args
  #  just echo them, but you may need to customize it according to your need
  # for example, F1 will store first field of $line, see readline2 script
  # for more examples
  # F1=$(echo $line | awk '{ print $1 }')

 # echo $line
}
 
### Main script stars here ###
# Store file name
FILE=""
 
# Make sure we get file name as command line argument
# Else read it from standard input device
if [ "$1" == "" ]; then
   FILE="/dev/stdin"
else
   FILE="$1"
   # make sure file exist and readable
   if [ ! -f $FILE ]; then
        echo "$FILE : does not exists"
        exit 1
   elif [ ! -r $FILE ]; then
        echo "$FILE: can not read"
        exit 2
   fi
fi
# read $FILE using the file descriptors
 
# Set loop separator to end of line
BAKIFS=$IFS
IFS=$(echo -en "\n\b")
exec 3<&0
exec 0<"$FILE"
while read -r line
do
        # use $line variable to process line in processLine() function
       n=""
       n=$(echo $line | /usr/xpg4/bin/awk -F"=" -v Ncnt="N" '$1==Ncnt { print $2 } ')
       if [ "$n" != "" ]; then
       for (( c=1; c<=$n; c++ ))
       do
          ......here i have to read the next line and filter out MSISDNs and SMSMSG
        processLine $line
done
exec 0<&3
 
# restore $IFS which was used to determine what the field separators are
IFS=$BAKIFS
exit 0

awk '/N=/ {
  val=substr($0,3);for(i=0;i<val;i++){
    pre="";if(i>0){pre="+"};getline;split($0, arr, "=");str=str pre arr[2];}
  getline;split($0, arr, "=");str=str"="arr[2];print str;str="";
}' file

awk -F= '/MSISDN/{s=(s=="")?$2:s"+"$2}/SMSMSG/{s=s"="$2;print s;s=""}' file

awk '{ printf "%s", $0; getline; printf "%s\n", $0 }' inputfile