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How to process only new line of tail -f command from live log file?

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# 1  
Old 10-17-2013
Linux How to process only new line of tail -f command from live log file?
Hi,

I want to read a live log file line by line and considering those line which are newly added to file
Below code I am using, which read line but as soon as it read new line from log file its starts processing from very first line of file.

Code:
tail -F /logs/COMMON-ERROR.log | while read myline; do
ERROR_CODE=$(echo $ myline | awk -F ' ' '{for (i=1;i<=NF;i++){if($i ~ "^[1-1]" && length($i)==6){print $i}}}')
ERROR_CODE_DET=$(echo $ myline | awk -F ' ' '{print $1" "$2}')
echo "$ERROR_CODE_DET" "$ERROR_CODE"

if [ "$ERROR_CODE" -eq 100021 ] ; then
ERROR_MSG="Route failed. Moving to failed routes pool."
fi
done

Last edited by vbe; 10-17-2013 at 10:50 AM.. Reason: code tags + rm fancy fonts...
# 2  
Old 10-17-2013
Try tail -n0 -F /logs/COMMON-ERROR.log |....
# 3  
Old 10-17-2013
This thread may also help
# 4  
Old 10-17-2013
Quote:
Originally Posted by CarloM
Try tail -n0 -F /logs/COMMON-ERROR.log |....
tail -n0 -F giving same output after reciving new file in log file .....Smilie
# 5  
Old 10-17-2013
Does it work with --follow=name rather than -F?
# 6  
Old 10-17-2013
Could it be the upper case F? from man tail:
Quote:
-f, --follow[={name|descriptor}]
output appended data as the file grows; -f, --follow, and --follow=descriptor are equivalent

-F same as --follow=name --retry

.
.
.
--retry
keep trying to open a file even when it is or becomes inaccessible; useful when following by name, i.e., with --follow=name
May be lower case f does not reopen the file?
# 7  
Old 10-17-2013
My suspicion was that the implied --retry is the problem.
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