Shell script: Merge files from within a date range [duplicate] - linux

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Extract data from log file in specified range of time [duplicate]
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I'd like to merge several log files within a given date range. For example, I have 5 days of log files in a directory:
server.log.2016-04-14-00
server.log.2016-04-14-01
. . .
server.log.2016-04-18-23
server.log.2016-04-19-00
server.log.2016-04-19-01
I know I can use cat to merge the files, but how can I code in a shell script so that only the files between, for example, 2016-04-17-22 and 2016-04-18-01 are selected?

Answer 1

The following script accepts server's log file as its first argument.
Two important variables are from_date and to_date which control the from-to range. They're hard-coded in the script, and you might want to change this to enhance script's usage flexibility.
#!/bin/bash
# Server's log file.
server_log_file=$1
# The date from which the relevant part of the log file should be printed.
from_date='2016/04/14 00:00'
# The date until which the relevant part of the log file should be printed.
to_date='2016/04/19 01:00'
# Uses 'date' to convert a date to seconds since epoch.
# Arguments: $1 - A date acceptable by the 'date' command. e.g. 2016/04/14 23:00
date_to_epoch_sec() {
local d=$1
printf '%s' "$(date --date="$d" '+%s')"
}
# Convert 'from' and 'to' dates to seconds since epoch.
from_date_sec=$(date_to_epoch_sec "$from_date")
to_date_sec=$(date_to_epoch_sec "$to_date" )
# Iterate over log file entries.
while IFS=. read -r s l date; do
# Read and parse the date part.
IFS=- read -r y m d h <<< "$date"
# Convert the date part to seconds since epoch.
date_sec=$(date_to_epoch_sec "$y/$m/$d $h:00")
# If current date is within range, print the enire line as it was originally read.
if (( date_sec > from_date_sec && date_sec < to_date_sec )); then
printf '%s.%s.%s\n' "$s" "$l" "$date"
fi
done < "$server_log_file"
In order to test it I created the following file, named logfile:
server.log.2016-04-14-00
server.log.2016-04-14-01
server.log.2016-04-18-23
server.log.2016-04-19-00
server.log.2016-04-19-01
Usage example ( script name is sof ):
$ # Should print logs from 2016/04/14 00:00 to 2016/04/19 01:00
$ ./sof logfile
server.log.2016-04-14-01
server.log.2016-04-18-23
server.log.2016-04-19-00