Retrieve last 100 lines logs

Question

I need to retrieve last 100 lines of logs from the log file  I tried the sed command  sed -n -e  100  p  logfilename   Please let me know how can I change this command to specifically retrieve the last 100 lines

User · Answer

You can simply use the following command:-

tail -NUMBER_OF_LINES FILE_NAME

e.g tail -100 test.log

will fetch the last 100 lines from test.log

In case, if you want the output of the above in a separate file then you can pipes as follows:-

tail -NUMBER_OF_LINES FILE_NAME > OUTPUT_FILE_NAME

e.g tail -100 test.log > output.log

will fetch the last 100 lines from test.log and store them into a new file output.log)

User · Answer

Look  the sed script that prints the 100 last lines you can find in the documentation for sed  https   www gnu org software sed manual sed html tail      cat sed cmd 1     H  g    1 100  s    n   n    p    sed -nf sed cmd logfilename   For me it is way more difficult than your script so   tail -n 100 logfilename   is much much simpler  And it is quite efficient  it will not read all file if it is not necessary  See my answer with strace report for tail   huge-file  https   unix stackexchange com questions 102905 does-tail-read-the-whole-file 102910 102910

User · Answer

tail  is command to display the last part of a file  using proper available switches helps us to get more specific output  the most used switch for me is -n and -f  SYNOPSIS     tail  -F   -f   -r   -q   -b number   -c number   -n number   file        Here      -n number                  The location is number lines       -f       The -f option causes tail to not stop when end of file is   reached  but rather to wait for additional data to be appended to the   input   The -f option is ignored if the                standard input is a pipe  but not if it is a FIFO    Retrieve last 100 lines logs  To get last static 100 lines        tail -n 100  lt file path gt   To get real time last 100 lines      tail -f -n 100  lt file path gt

User · Answer

len  cat filename   wc -l  len      len   1    l      len - 99    sed -n    l    len p  filename   first line takes the length  Total lines  of file then  1 in the total lines after that we have to fatch 100 records so  -99 from total length then just put the variables in the sed command to fetch the last 100 lines from file  I hope this will help you

User · Answer

I know this is very old  but  for whoever it may helps   less  F my log file log  that s just basic  with less you can do lot more powerful things  once you start seeing logs you can do search  go to line number  search for pattern  much more plus it is faster for large files   its like vim for logs totally my opinion   original less s documentation   https   linux die net man 1 less   less cheatsheet   https   gist github com glnds 8862214

User · Answer

You can use tail command as follows   tail -100  lt log file gt     gt  newLogfile   Now last 100 lines will be present in newLogfile  EDIT   More recent versions of tail as mentioned by twalberg use command   tail -n 100  lt log file gt     gt  newLogfile

[linux] Retrieve last 100 lines logs

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