Here is a script that should do what you want. The
number of lines to print (5 in your example), input
file name and search pattern at set at the top so
that you can change them. Consider modifying the
script to use command line parameters. The script
will print 11 lines if pattern matches (i.e 5 previous
and 5 following lines and the line itself that matches.
NOTE : The script does not behave nicely if the
patter matches first or last 5 lines. Modifying the
script to do that is left as an exercise to original
poster ;-)
------ Start -----
#!/usr/bin/ksh
# Set the following parameters
integer LINES_TO_PRINT=5
INPUT_FILE_NAME="testfile"
SEARCH_PATTERN="stu"
# Executation starts from here
LINES_TO_READ=$(echo \
"2*$LINES_TO_PRINT+1" | bc )
exec 3<$INPUT_FILE_NAME
integer i=1
while [ /bin/true ]
do
if [ $i -gt $LINES_TO_READ ]
then
break
fi
read -ru3 line[$i]
i=$i+1
done
integer MIDDLE_LINE=$LINES_TO_PRINT+1
while [ /bin/true ]
do
integer j=1
echo ${line[$MIDDLE_LINE]} | grep -q \
$SEARCH_PATTERN
if [ $? -eq 0 ]
then
while [ $j -le $LINES_TO_READ ]
do
echo ${line[$j]}
j=$j+1
done
fi
j=1
while [ $j -lt $LINES_TO_READ ]
do
line[$j]=${line[$j+1]}
j=$j+1
done
read -ru3 line[$j]
if [ $? -ne 0 ]
then
exit
fi
done
- Biswajit
:-)
