Shell Programming and Scripting

while read line; do
    echo "${line}"
done < 'file'

    if [ "A: "${input} = "${line}" ]; then 
        read line2; read line3; 
        #echo or another thing to do with both lines
        echo "${line2}"; echo "${line3}"
    fi

line2=$(echo "${line2}" | sed 'script')

#!/bin/sh

read -p'A input: ' inputA

while read line; do
    if [ "A: "${inputA} = "${line}" ]; then 
        read lineB; read lineC
        match='true'
        break
    fi
done < 'file'

if [ ${match} = 'true' ]; then
    read -p'input C: ' inputC
    sed -i 's/'"${lineC}"'/C: '"${inputC}"'/' 'file'
fi

exit 0