How to crop cut text files based on starting and ending line-numbers in cygwin

Question

I have few log files around 100MBs each   Personally I find it cumbersome to deal with such big files  I know that log lines that are interesting to me are only between 200 to 400 lines or so   What would be a good way to extract relavant log lines from these files ie I just want to pipe the range of line numbers to another file   For example   the inputs are   filename  MyHugeLogFile log Starting line number  38438 Ending line number    39276   Is there a command that I can run in cygwin to cat out only that range in that file  I know that if I can somehow display that range in stdout then I can also pipe to an output file   Note  Adding Linux tag for more visibility  but I need a solution that might work in cygwin   Usually linux commands do work in cygwin

User · Answer

This is an old thread but I was surprised nobody mentioned grep. The -A option allows specifying a number of lines to print after a search match and the -B option includes lines before a match. The following command would output 10 lines before and 10 lines after occurrences of "my search string" in the file "mylogfile.log":

grep -A 10 -B 10 "my search string" mylogfile.log

If there are multiple matches within a large file the output can rapidly get unwieldy. Two helpful options are -n which tells grep to include line numbers and --color which highlights the matched text in the output.

If there is more than file to be searched grep allows multiple files to be listed separated by spaces. Wildcards can also be used. Putting it all together:

grep -A 10 -B 10 -n --color "my search string" *.log someOtherFile.txt

User · Answer

You can use wc -l to figure out the total   of lines   You can then combine head and tail to get at the range you want   Let s assume the log is 40 000 lines  you want the last 1562 lines  then of those you want the first 838   So   tail -1562 MyHugeLogFile log   head -838          Or there s probably an easier way using sed or awk

User · Answer

And if you simply want to cut part of a file - say from line 26 to 142 - and input it to a newfile   cat file-to-cut txt   sed -n  26 142p   gt  gt  new-file txt

User · Answer

I saw this thread when I was trying to split a file in files with 100 000 lines  A better solution than sed for that is   split -l 100000 database sql database-   It will give files like   database-aaa database-aab database-aac

User · Answer

How about this     seq 1 100000   tail -n  10000   head -n 10 10000 10001 10002 10003 10004 10005 10006 10007 10008 10009   It uses tail to output from the 10 000th line and onwards and then head to only keep 10 lines   The same  almost  result with sed     seq 1 100000   sed -n  10000 10010p  10000 10001 10002 10003 10004 10005 10006 10007 10008 10009 10010   This one has the advantage of allowing you to input the line range directly

User · Answer

Sounds like a job for sed   sed -n  8 12p  yourfile      will send lines 8 through 12 of yourfile to standard out   If you want to prepend the line number  you may wish to use cat -n first   cat -n yourfile   sed -n  8 12p

User · Answer

If you are interested only in the last X lines  you can use the  tail  command like this     tail -n XXXXX yourlogfile log  gt  gt  mycroppedfile txt   This will save the last XXXXX lines of your log file to a new file called  mycroppedfile txt

[linux] How to crop(cut) text files based on starting and ending line-numbers in cygwin?

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