Get unique values from a column only from lines starting with certain string in csh using awk

Question

I am trying to obtain a list of hosts from this influxdb query:

$ influx -database "collectd" -execute "SHOW TAG VALUES WITH KEY=host"

The output is something like:

name: system
key   value
------------
host  foo.tld
host  bar.tld

name: mem
key   value
------------
host  foo.tld
host  bar.tld

...

Currently, I am using awk like this:

$ db-query | awk '/^host/ && !a[$2]++ { print $2 }'

This works when using shell sh and returns only the list of unique hosts, for example:

foo.tld
bar.tld

But when using csh shell I get this error:

a[: Event not found.

Any idea how to achieve this being portable in both sh and csh shells?

Answer 1

Try escaping any/all ! chars like \!

The csh interprets the ! char as events in the command history.

The most common "events" used are !! (previous line), and !$ (last word in previous line), but there are a million more.

I'm surprised you're getting that error msg, as I thought csh honored single-quotes.(but apparently not;-) ).

IHTH