Need command for grepping pattern lines with subsequent lines

UNIX for Advanced & Expert Users
1

Hi,

I have a requirement like, I have a list of pattens in a file say pattern.txt,

PHC111
PHC113

and in another file called master.lst i have entries like,

PHC111
a
b
PHC112
a
PHC113
b
c
PHC114
d
e
PHC115

now i want to use the pattern.txt file as patterns and grep the lines in master.lst so that i will get output like,

PHC111
a
b
PHC113
b
c

Please suggest the suitable command. Thanks.

2

What have you tried?

3

Do the PHC lines ALWAYS start with "PHC"?
It helps to exactly describe the problem.

4

Also, what's your OS? (more specifically, do you have GNU grep?)

5

you can use this code if your PHC line always starts with "PHC"

here pattern.txt contain your pattern list
and mint.txt contains your data

while read pat
do
count=2
while read line
do
b=`echo $line|grep PHC`
if [ $? -eq 0 ]
then
if [ $count -eq 1 ]
then
break;
break;
fi
a=`echo $line|grep $pat`
if [ $? -eq 0 ]
then
count=`echo "$count-1"|bc`
fi
fi
if [ $count -eq 1 ]
then
echo $line
fi
done<mint.txt
done<pattern.txt
6

Using while loop:

while read line;do egrep -A2 $line file2;done < file1

PHC111
a
b
PHC113
b
c

Using awk:

awk 'FNR==NR {a[$1];next} $1 in a {print;getline;print;getline;print}' file1 file2

PHC111
a
b
PHC113
b
c