Cropping the relevant section from a log file

Cropping the relevant section from a log file

# 1) get line number of first relevant log line: (e.g. by date 2014-01-13 13:49)
grep "2014-01-13 13:49" original.log -n | more

# 2) get line number of last relevant log line: (e.g. by date 2014-01-13 16:36)
grep "2014-01-13 16:36" original.log -n | more

# 3) the total number of lines from the original log file:
wc -l original.log -n

# e.g. results of 1-3:
# - from: 2148520
# - to: 3621984
# - length: 3666691

# 4) create the cropped file using a command similar to
# head -n (TO) orig.log | tail -n (TO-FROM)
# in our concrete example:
head -n 3621984 orig.log | tail -n 1473464 > relevant_only.log

# (if you need to use it frequently script all this)!