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Full Discussion: Delete first 100 lines from a BIG File
Top Forums UNIX for Advanced & Expert Users Delete first 100 lines from a BIG File Post 302659365 by methyl on Wednesday 20th of June 2012 07:27:33 PM
Old 06-20-2012
IMHO @drl's solution in post #15 nearly fulfils the requirement.

Reading between the lines, we are again presented with a faulty solution without a definition of the actual problem.

Taking into account Corona688's comment about inodes, this code would be safer on most unix/Linux Operating Systems:
Code:
cp test.log back.log
sed '1,100d' test.log>temp.log 
cat temp.log > test.log


I have used a similar code construct (albeit with grep -v)to remove persistent irrelevant entries from a system log where it was causing unwanted alerts (pending a fix).
Last edited by methyl; 06-20-2012 at 08:55 PM..
This User Gave Thanks to methyl For This Post:
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LEARN ABOUT CENTOS

doveadm-log

DOVEADM-LOG(1)							      Dovecot							    DOVEADM-LOG(1)

NAME

       doveadm-log - Locate, test or reopen Dovecot's log files

SYNOPSIS

       doveadm [-Dv] log errors [-s min_timestamp]
       doveadm [-Dv] log find [directory]
       doveadm [-Dv] log reopen
       doveadm [-Dv] log test

DESCRIPTION

       The  doveadm  log commands are used to locate and reopen the log files of dovecot(1).  It's also possible to test the configured targets of
       the *log_path settings.

OPTIONS

       Global doveadm(1) options:

       -D     Enables verbosity and debug messages.

       -v     Enables verbosity, including progress counter.

COMMANDS

   log errors
       doveadm log errors [-s min_timestamp]

       The log errors command is used to show the last	- up to 1,000 - errors and warnings.  If no output is generated, no errors  have  occurred
       since the last start.

       -s min_timestamp
	      An  integer  value, representing seconds since the epoch - also known as Unix timestamp.	When a min_timestamp was given, doveadm(1)
	      will only show errors occurred since that point in time.

   log find
       doveadm log find [directory]

       The log find command is used to show the location of the log files, to which dovecot(1) sends its log messages.	 If  dovecot(1)  logs  its
       messages  through  syslogd(8)  and doveadm(1) could not find any log files, you can specify the directory where your syslogd writes its log
       files.

   log reopen
       doveadm log reopen

       This command causes doveadm to reopen all log files, configured in the log_path, info_log_path and debug_log_path settings.  These settings
       are configured in /etc/dovecot/conf.d/10-logging.conf.
       This is for example useful after manually rotating the log files.

   log test
       doveadm log test

       This command causes doveadm to write the message "This is Dovecot's priority log (timestamp)" to the configured log files.  The used prior-
       ities are: debug, info, warning, error and fatal.

EXAMPLE

       This example shows how to locate the log files used by dovecot(1).

       doveadm log find
       Looking for log files from /var/log
       Debug: /var/log/dovecot.debug
       Info: /var/log/mail.log
       Warning: /var/log/mail.log
       Error: /var/log/mail.log
       Fatal: /var/log/mail.log

REPORTING BUGS

       Report bugs, including doveconf -n output, to the Dovecot Mailing List <dovecot@dovecot.org>.  Information about reporting bugs	is  avail-
       able at: http://dovecot.org/bugreport.html

SEE ALSO

       doveadm(1)

Dovecot v2.2							    2013-11-24							    DOVEADM-LOG(1)
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