Difference between revisions of "Grep"
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=Using grep= | =Using grep= | ||
<strong>Recursively search DIR for "STRING" (also ignores caps)</strong> | <strong>Recursively search DIR for "STRING" (also ignores caps)</strong> | ||
| − | grep - | + | grep -irl "STRING" /DIR/ |
<strong>Piping</strong> | <strong>Piping</strong> | ||
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cat file.txt | grep '^firstline' | cat file.txt | grep '^firstline' | ||
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| + | Recursively grep for STRING within /DIR using 8 threads in parallel: | ||
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| + | find /DIR -type f | parallel -k -j8 -n 1000 -m grep -H -n -ril STRING {} | ||
Latest revision as of 10:55, 18 July 2019
grep searches the named input FILEs (or standard input if no files are named, or if a single hyphen-minus (-) is given as file name) for lines containing a match to the given PATTERN. By default, grep prints the matching lines. grep is a powerful tool.
Using grep
Recursively search DIR for "STRING" (also ignores caps)
grep -irl "STRING" /DIR/
Piping
grep can also be piped from or to other outputs using the pipe "|"
grep "STRING" /LOCATION/logfile.log |grep ANOTHERSTRING
Example usage:
grep "13:00:" /var/log/messages |grep "September"
tail -f /var/log/somefile.log |grep specificstring
sudo cat /usr/local/apache/logs/error_log | grep -i "modsec" | awk '{print $10}' | sort | uniq -c | sort -n
Remove everything but grep'd
This will show only lines with "firstline" within file.txt.
cat file.txt | grep '^firstline'
Recursively grep for STRING within /DIR using 8 threads in parallel:
find /DIR -type f | parallel -k -j8 -n 1000 -m grep -H -n -ril STRING {}
