Whois scraping bash script—if clause errors

Question

I wrote a fairly straightforward script to map out what one-word domains are still available. I'm getting an error in line 7, the if clause, but I can't see anything wrong with it.

#!/bin/bash

for i in $(cat /usr/share/dict/words);
do
        i="$i.com"
        echo $i processing `date`
        if [ $(whois $i) == "*No match for*" ]
        then
                echo $i AVAILABLE
#               echo "$i">>domains.available.`date "+%Y%m%d"`
        else
                echo $i unavailable
#               echo "$i">>domains.unavailable.`date "+%Y%m%d"`
        fi
done

I looked up similarly straightforward scripts online, and they seem syntactically identical.

Side remark: the absence of a WHOIS record does not necessarily imply that a domain is available. — Alex Riley, Nov 09 '15 at 22:11
Oh, sure; it just provides a starting point to begin manual enquiries. — RPNS, Nov 09 '15 at 22:12

score 1 · Accepted Answer · answered Nov 09 '15 at 22:16

1

Try double brackets and the * outside the quotes

if [[ $(whois $i) == *"No match for"* ]]

answered Nov 09 '15 at 22:16

papkass

1,261
2
14
20

score 1 · Answer 2 · answered Nov 09 '15 at 22:16

1

Quote the argument:

if [ "$(whois $i)" == "*No match for*" ]

Otherwise all the words of the response will be split into separate arguments to the test command.

Or you could use the built-in conditional operator. It doesn't do word splitting of variables or command substitutions.

if [[ $(whois $i) == "*No match for*" ]]

answered Nov 09 '15 at 22:16

Barmar

741,623
53
500
612

The latter (double-brackets for the built-in conditional operator) does in fact resolve the error, but silently gives me false negatives consistently. In other words, `$i=notarealdomainatall.com` still flows to the else block. – RPNS Nov 09 '15 at 22:23
Are you expecting `==` to do a pattern match instead of an exact match? Wildcards inside quotes are not considered pattern characters. – Barmar Nov 09 '15 at 22:24
Ah, yes I was! '*No match for*' is an unlikely literal string to result from a whois query ;-) – RPNS Nov 09 '15 at 22:27

Whois scraping bash script—if clause errors

2 Answers2