Bash script to sort input file before piping to while loop

Question

I have this bash script:

while IFS='"' read -r a ip c
do
    echo "ip: $ip"
    whois "$ip" | grep netname
done < <(head -10 file.log)

How can I sort the file.log file (e.g. with sort -n -r) before the first ten lines are taken and handed over to the while-loop?

fedorqui · Accepted Answer · 2015-01-14 11:29:51Z

3

If you want to get the top 10 lines after sorting, just sort it before using head:

while IFS='"' read -r a ip c
do
    echo "ip: $ip"
    whois "$ip" | grep netname
done < <(sort file.log | head -10)
         ^^^^^^^^^^^^^^^

Apply the sort flags you require, of course.

answered Jan 14, 2015 at 11:29

fedorqui

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Comments

Arnab Nandy · Accepted Answer · 2015-01-14 11:35:34Z

0

Use this command,

sort -nr file.log | head -10

answered Jan 14, 2015 at 11:27

Arnab Nandy

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this will sort the top 10 lines, whereas the OP probably wants to get the top 10 sorted lines