Ytdyklly

I have a list of timestamped filenames in this following format:

cat files

• ..201807010112.log


• ..201807020112.log


• ..201807022359.log


• ..201807030112.log


• ..201807010412.log

I need to get a certain range and in order to do this, I'd like to use SED.

sed -n '/201807010112/,/201807030112/p' 

Was my first attempt but sed treats the hour and minute strangely, and to make a long story short it's unable to understand this format correctly.

I may be getting in the weeds but in order to solve this, I've decided to convert the format to something SED understands.

cat files | sed -e "s/([0-9]{12}}/$(date -f '%Y%m%d%H%M' 1)/g"

My problem is that I cannot use the result of the match 1 in the date conversion block.

Is there a way to do this or better yet a better way to get the range of dates?

Your question states that you need to get the names of some log files in a certain date range.

Let's disregard the fact that you have the filenames in a text file and instead assume that you have direct access to the files in some directory $logdir.

The format of the filenames are *_YYYYMMDDhhmmss.log where the end bit is a standard timestamp string.

To get the files between *_201807010112.log and *_201807030112.log in a loop (to do something to each of them), use (in bash),

process_flag=0



for pathname in "$logdir"/*_??????????????.log

do

    if [ "$process_flag" -eq 0 ]; then

        if [[ "$pathname" == *_201807010112.log ]]; then

            process_flag=1

        else

            continue

        fi

    fi





    # Do some sort of processing of

    # the logfile in "$pathname" here.





    # When done...



    if [[ "$pathname" == *_201807030112.log ]]; then

        break

    fi

done

This loop loops over all logfiles that have a similar filename format. The loop will iterate over the pathnames in lexicographical order. It is assumed that all files have the same filename prefix (you say nothing about this).

The first part of the loop detects the first file in the range and sets process_flag to 1 when that file is found. Setting process_flag to 1 enables the loop to get into the middle bit where you actually use "$pathname" for whatever processing of that file that you need doing.

Before continuing with the next iteration, the last if statement checks to see whether the current $pathname matches the last file that we wanted to process. If it does, the loop ends by a break statement.

So I decided not to try to use date function to transform the form and instead use more SED!

cat files

• 
  

  ..._201807010112.log

  
  




• 
  

  ..._201807010132.log

  
  




• 
  

  ..._201807010152.log

  
  




• 
  

  ..._201807010202.log

  
  

The date is in the format YYYYmmddHHSS and I transformed it to the following format:

YYYY-mm-dd HH:SS using this regex expression with SED.

cat files | sed -e 's/(_[0-9]{4})([0-9]{2}) 

([0-9]{2})([0-9]{2})([0-9]{2}) /1-2-3 4:5/g'

Next, from there it was a piece of cake to specify the range based on date.

  | sed -n '/2018-07-01 01:20/,/2018-07-02 02:01/p'

The biggest take away for me was knowing the proper date-time format to utilize SED's range pattern option.