cool sed/grep magic to convert output to csv format

2019-03-11 1 min read bash Learning

I generallly keep doing this a lot, so thought will share with you. Lets assume we are capturing free ouput every min/hour/or whatever. The output looks like this:

Time: Mon Jan 21 23:59:10 AEDT 2019
——————-

total        used        free      shared  buff/cache   available
Mem:          32014        8656        1735        1697       21621       21308
Swap: 51195 75 51120

then we can use some grep and sed to convert this to something like this:

Mon Jan 21 23:59:10 AEDT 2019,32014,8656,1735,1697,21621,21308

This is the code that I used for this:

zgrep -E '^(Time|Mem):' free.20190121.gz |sed -E '/Mem/ s/\s+/,/g'|sed -E 's/^(Time|Mem):\s*//' |sed   ':a;$!N;s/\n//;P'
Explanation:

use zgrep to get the line starting with time or mem
use sed to convert multiple spaces to single space
use sed again to get only the line containing Memory or time
use sed the last time to merge the 2 lines
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