Feb 172016
 

This is a silly script but you would be surprised how many times a day I have to do this and no matter how many times I type the command, I always get it wrong (or more than likely I forget to escape something).  Its also interesting to note that the scripts I find silly are usually the ones that are the most popular on this site….so here it is.

Basically, if you copy and paste this script into a file and run it, it will give you the exact date and time in the sed command to run to search all lines in a log file from the previous hour to now and save it to another file.

#!/bin/bash
#===============================================================================
#
#          FILE:  determine-time.sh
# 
#         USAGE:  ./determine-time.sh 
# 
#   DESCRIPTION:  determines current date and time and previous hour for searching
#                 files between date and time using sed (example does previous hour)
#  REQUIREMENTS:  sed
#        AUTHOR:  Ed Wiget
#       VERSION:  1.0
#       CREATED:  02/17/2016 04:10:53 PM EST
#
#===============================================================================
 
# current year
CY=`date +%Y`
# current month
CM=`date +%b`
# current day of month
CD=`date +%d`
# current hour
CH=`date +%H`
# current minute
CMH=`date +%M`
# current second
CS=`date +%S`
 
echo "The current date and time is: ${CY}-${CM}-${CD} ${CH}:${CMH}:${CS}"
 
echo ""
 
# now determine previous hour
PH=`expr ${CH} - 1 `
 
echo "the previous hour is: ${PH}"
 
echo ""
 
# for sed we need this format
# sed -n '/27\/Mar\/2013\:16\:00\:00/,/27\/Mar\/2013\:16\:16\:00/ p' merged.log > 12_00_00-12_16_00EST_16_00_00-16_16_00UTC.txt
echo "our search beginning time in sed is:"
echo "/${CD}\/${CM}\/${CY}\:${PH}\:${CMH}\:${CS}/"
 
echo ""
 
echo "our search ending time in sed is:"
echo "/${CD}\/${CM}\/${CY}\:${CH}\:${CMH}\:${CS}/"
 
echo ""
echo "The entire sed command to search logs from previous hour to now is:"
echo "sed -n '/${CD}\/${CM}\/${CY}\:${PH}\:${CMH}\:${CS}/,/${CD}\/${CM}\/${CY}\:${CH}\:${CMH}\:${CS}/ p' /path/to/log/filename > /path/to/output_filename.txt"

 

So when you run it, it basically looks like this:

$ scripts/determine-time.sh
The current date and time is: 2016-Feb-17 16:50:51
 
the previous hour is: 15
 
our search beginning time in sed is:
/17\/Feb\/2016\:15\:50\:51/
 
our search ending time in sed is:
/17\/Feb\/2016\:16\:50\:51/
 
The entire sed command to search logs from previous hour to now is:
sed -n '/17\/Feb\/2016\:15\:50\:51/,/17\/Feb\/2016\:16\:50\:51/ p' /path/to/log/filename > /path/to/output_filename.txt

This is a much better version of the above script …

#!/bin/bash
#===============================================================================
#
#          FILE:  sed_time2.sh
# 
#         USAGE:  ./sed_time2.sh 
# 
#   DESCRIPTION:  
# 
#       OPTIONS:  ---
#  REQUIREMENTS:  ---
#          BUGS:  ---
#         NOTES:  ---
#        AUTHOR:  Ed Wiget (), [email protected]
#       COMPANY:  
#       VERSION:  1.0
#       CREATED:  04/28/2017 11:25:39 AM EDT
#      REVISION:  ---
#===============================================================================
 
if [ "$1" = "" ]; then
	echo "how long ago as starting time in minutes, i.e. 30 for 30 minutes"
	read PTIME
else
	PTIME=$1
fi
 
# current time
DNOW=`date +%d/%b/%Y:%H:%M:%S`
 
# time formatted escaped sed ready
ESCAPED_DNOW=`echo ${DNOW} | sed 's,/,\\\/,g' | sed 's,:,\\\:,g'`
 
# previous time
PDATE=`date +%d/%b/%Y:%H:%M:%S --date="${PTIME} minutes ago"`
 
# time formatted escaped sed ready
ESCAPED_PDATE=`echo ${PDATE} | sed 's,/,\\\/,g' | sed 's,:,\\\:,g'`
 
# now we can simply echo the sed line
echo "sed -n '/${ESCAPED_PDATE}/,/${ESCAPED_DNOW}/ p'"