Print file in particular order in bash

Question

I have file with content:

file.txt:

Iteration 1
RAM: +456ms
Cache: +142ms (total +417ms)

Iteration 2
Spec: +152ms
Cache: +149ms (total +413ms)

Iter         


        

Answer 1

One using awk:

$ awk '
$1 !~ /^(|First)$/ {            # avoid forbidden keywords and empty lines
    gsub(/[^0-9]/,"",$2)        # remove non-numerals
    a[$1]=a[$1] OFS $2          # append to associative array 
}
END {                           # in the end
    for(i in a)                 # loop all keywords
        print i a[i]            # output
}' file

Output lines in awk default order (appears random):

Cache: 142 149
Searchms: 131 188
Spec: 152 172
RAM: 456 184 149