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Suppose I have a file which is getting appended in every seconds/minutes. At first time I have read whole file and stored the last line number(eg: last_line_numer was : 2000) later I want to read file using 'grep' command to look for a pattern from line number 2001 to end of file. How we can achieve this?
First time I ran below command:
grep 'tracker.php' apache.log | cut -d' ' -f1-8
Now I want to ran above command with specific line number in grep param.
You can use tail to output the file from line number 2001 and pipe the result to your command:
<apache.log tail +2001 | grep 'tracker.php' | cut -d' ' -f1-8
cat -n apache.log | tail +2001 | grep -o '.*tracker.php[^"]*"'if we take the logfile from your other question
You can use
awk 'NR<2001 {next} /tracker.php/ {print NR, $1,$2,$3,$4,$5,$6,$7,$8}' apache.log
or
awk 'NR<2001 {next} /tracker.php/ {print NR, $0}' apache.log | cut -d' ' -f1-9
which will also display the original line numbers of the matching lines in the file.
Using sed:
sed '1,2000d; /tracker\.php/!d' | cut -d ' ' -f-8
That is, discard lines 1 through to 2000 (inclusively), and then also discard any line not containing the string tracker.php. Send the rest of the lines through cut.
