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Full Discussion: BASH logging to file, limit lines
Top Forums Shell Programming and Scripting BASH logging to file, limit lines Post 303002705 by RudiC on Thursday 31st of August 2017 03:31:55 AM
Old 08-31-2017
While Don Cragun's fine proposal works brilliantly, it preserves the line count on hand, be it 8 or 800. Try piping into this (shamelessly stolen from Don Cragun) to make log.txt exactly 20 lines long, no matter what its size be:
Code:
while IFS='' read -r line
  do    tail -19 log.txt > _log.txt
        { cat _log.txt
          printf '%s\n' "$line"
        } > log.txt
  done

This User Gave Thanks to RudiC For This Post:
Don Cragun
 

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LEARN ABOUT DEBIAN

x2sys_merge

X2SYS_MERGE(1gmt)					       Generic Mapping Tools						 X2SYS_MERGE(1gmt)

NAME

       x2sys_merge - Merge an updated COEs tables

SYNOPSIS

       x2sys_merge -Amain_COElist.d -Mnew_COElist.d

DESCRIPTION

       x2sys_merge  will read two crossovers data base and output the contents of the main one updated with the COEs in the second one. The second
       file should only contain updated COEs relatively to the first one.  That is, it MUST NOT contain any new  two  tracks  intersections  (This
       point  is  NOT checked in the code). This program is useful when, for any good reason like file editing NAV correction or whatever, one had
       to recompute only the COEs between the edited files and the rest of the database.

       -A     Specify the file main_COElist.d with the main crossover error data base.

       -M     Specify the file new_COElist.d with the newly computed crossover error data base.

OPTIONS

       No space between the option flag and the associated arguments.

       EXAMPLES
	      To update the main COE_data.txt with the new COEs estimations saved in the smaller COE_fresh.txt, try

	      x2sys_merge -ACOE_data.txt -MCOE_fresh.txt > COE_updated.txt

SEE ALSO

       x2sys_binlist(1), x2sys_cross(1), x2sys_datalist(1), x2sys_get(1), x2sys_init(1), x2sys_list(1), x2sys_put(1), x2sys_report(1)

GMT 4.5.7							    15 Jul 2011 						 X2SYS_MERGE(1gmt)
All times are GMT -4. The time now is 10:00 AM.
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