Shell Programming and Scripting

NAME
ADDRESS
NO
NAME
OTHER
NEW
OP
NAME
FEW

$ cat file.txt
NAME
ADDRESS
NO
NAME
OTHER
NEW
OP
NAME
FEW
OTHER
NEW
NAME

 
$ cat file1
grep -n "NAME" file.txt | cut -d ':' -f1 > /tmp/occurance_lines.txt
i=1
while read line
do
  if [[ ${i} -gt 3 ]]; then
    break
  fi
  line1=$(( ${line} - 1 ))
  if [[ line1 -ne 0 ]]; then
    tail +${line1} file.txt | head -1 >> /tmp/output.txt
  fi
  line2=$(( ${line} + 1 ))
  tail +${line2} file.txt | head -1 >> /tmp/output.txt
  i=$(( ${i} + 1 ))
done < /tmp/occurance_lines.txt
cat /tmp/output.txt
rm -f /tmp/occurance_lines.txt /tmp/output.txt

 
$ ./file1
ADDRESS
NO
OTHER
OP
FEW

grep -C1 "something" yourfile

% grep -C1 "ABC" pattern
grep: illegal option -- C
grep: illegal option -- 1
Usage: grep -hblcnsviw pattern file . . .

 
awk '/NAME/{getline;print prev;print $0;next}{prev=$0}' infile