Shell Programming and Scripting

if egrep -q 'ERROR|WARNING' myfile.txt; then

grep -A 10 -B 10 -E 'ERROR|WARNING' myfile.txt

grep -A 10 -B 10 -E 'ERROR' myfile.txt
grep: Not a recognized flag: A

#!/bin/sh

# open the file
exec 5<filename

# Read up to the first match.
# because of -m, grep will leave the open file on the line after it.
# Then print 10 more lines.
( grep -m 1 "MATCH" && head -n 10 ) <&5

# close the file
exec 5<&-

#!/bin/ksh

TMP="/tmp/$$"

while read LINE
do
        if [[ "${LINE}" == *ERROR* ]] || [ "${LINE}" == *WARNING* ]]
        then
                tail -n 10 "$TMP"
                echo "$LINE"
                head -n 10
                : > "$TMP"
        else
                echo "$LINE" >> "$TMP"
        fi
done < inputfile

rm -f "$TMP"

#!/bin/ksh

TMP="/tmp/$$"

CONTEXT=0

while read LINE
do
        if [[ "${LINE}" == *ERROR* ]] || [ "${LINE}" == *WARNING* ]]
        then
		[[ "${CONTEXT}" -le 0 ]] && tail -n 10 "$TMP"
		CONTEXT=10
        fi

	if [[ "${CONTEXT}" -gt 0 ]]
	then
		echo "${LINE}"
	fi

        echo "${LINE}" >> "$TMP"

	((CONTEXT--))

done < inputfile

rm -f "$TMP"