Bash while loop with two string conditions

Question

I have run into a bit of a problem with my bash script. My script among other things is starting a server that takes some time to get going. In order to combat the long startup, I have put in a while loop that queries the server to see if its running yet.

while [ $running -eq 0 ]; do
echo "===" $response "===";
if [ "$response" == "" ] || [ "$response" == *"404 Not Found"* ]; then
    sleep 1;
    response=$(curl $ip:4502/libs/granite/core/content/login.html);
else
   running=1;
fi
done

When exiting the loop $response equals the "404" string. If thats the case, the thing should still be in the loop, shouldn't it? Seems my loop is exiting prematurely.

Joe

that other guy · Accepted Answer · 2013-07-09 00:08:16Z

6

[ .. ] doesn't match by glob. Use [[ .. ]]:

if [ "$response" == "" ] || [[ "$response" == *"404 Not Found"* ]]; then

answered Jul 9, 2013 at 0:08

that other guy

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6 Comments

Gordon Davisson Over a year ago

Note that [[ ]] is a bash extension, so make sure the script starts with #!/bin/bash, not #!/bin/sh. There are ways to do an equivalent test in plain POSIX shell syntax, but they aren't nearly as clean.

Joe Andolina Over a year ago

Thank you for the answer, but even with your changes, I am still seeing the loop exiting while response has the 404 string in it.

Preet Sangha Over a year ago

@JoeAndolina Just a thought - have you verified this with another site that definitely gives a 404?

Joe Andolina Over a year ago

@Preet, My output in the loop is surrounded with === and my output after the loop is surrounded with +++, === <html><head><title> 404 Not Found </title>... ===, - after - +++ <html><head><title> 404 Not Found </title>... +++,

that other guy Over a year ago

@JoeAndolina Your echo statement destroyed whitespace, so if the text contained e.g. two spaces or a no-break space, it would print the same but not match. echo "$response" > file with quotes would let you investigate.

|

Joe Andolina · Accepted Answer · 2013-07-09 02:20:36Z

0

I am not sure why my original script was failing. I assume it has to do with the fact that I was comparing against HTML. To get my script working I wound up using the string length instead of the content. The using the following comparator has everything working swimmingly.

if [ -z "$response" ] || [ ${#response} -lt 100 ]; then

Thanks for the help, Joe

answered Jul 9, 2013 at 2:20

Joe Andolina

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