[SOLVED] curl not working in a bash script

[Cheesehead]

=== Solved - see the solution at the bottom of the first post (this one) ===

The following executes beautifully on the command line:


ian@apathy:~$ curl http://www.whatismyip.com/automation/n09230945.asp
xxx.xxx.xxx.xxxian@apathy:~$


But in the following script, it fails...looking for ideas on how to fix it!

Script:

#!/bin/sh
external_ip=curl http://www.whatismyip.com/automation/n09230945.asp
echo "My IP address is: "$external_ip
echo "End!"

Output:

ian@apathy:~$ ./curl_test.sh
./curl_test.sh: 2: http://www.whatismyip.com/automation/n09230945.asp: not found
My IP address is:
End!
ian@apathy:~$


=== SOLUTION ===

I needed to put the curl command in quotes...the right kind of quotes (slanted quotes found on the tilde '~' key on a US keyboard.

The final script that works great is:

#!/bin/sh
external_ip=`curl http://www.whatismyip.com/automation/n09230945.asp`
echo "My IP address is: "$external_ip
echo "End!"

Thanks to everyone for their help...

[whitethorn]

Well I'm not really sure why it doesn't work. But I got it to work. Only problem is it's not all in one line.



#!/bin/sh
$external_ip
echo "My external IP address is"; curl http://www.whatismyip.com/automation/n09230945.asp; echo " End!"

[jamesrl]

#!/bin/sh
external_ip=`curl http://www.whatismyip.com/automation/n09230945.asp`
echo "My IP address is: "$external_ip
echo "End!"

works for me by adding the ` ` quotes around the command.
Also note, this is a sh shell script (hence the #!/bin/sh as opposed to #!/bin/bash for a bash script).

[jamesrl]

Also in general when debugging a sh/bash script, it helps to display output from the file.
So run

bash -xv temp.sh
-v is for 'verbose' (write the each line of the script to standard error before it is run), and
-x is for writing each command that gets executed to standard error.

So for your original script you get:

#!/bin/sh
external_ip=curl http://www.whatismyip.com/automation/n09230945.asp
+ external_ip=curl
+ http://www.whatismyip.com/automation/n09230945.asp
temp.sh: line 2: http://www.whatismyip.com/automation/n09230945.asp: No such file or directory
echo "My IP address is: "$external_ip
+ echo 'My IP address is: '
My IP address is:
echo "End!"
+ echo 'End!'
End!

So you can immediately see the problem, bash ran the command curl with no arguments, set the output to external_ip, and then tried running http://www.whatismyip.com/automation/n09230945.asp as a seperate command.

For more help http://tldp.org/LDP/abs/html/, though for all but the simplest scripts, I would strong recommend trying python for your scripts.

[Cheesehead]

1) Okay, so it's a dash script. Got it. Is there an important difference?

2) I need to save the IP address as a variable - that's the point of the test. I plan to use it later.

3) Suggested single-quotes works great, but still doesn't give me what I want:
Script:

#!/bin/sh
external_ip='curl http://www.whatismyip.com/automation/n09230945.asp'
echo "My IP address is: "$external_ip
echo "End!"

Output:

ian@apathy:~$ ./curl_test.sh
My IP address is: curl http://www.whatismyip.com/automation/n09230945.asp
End!
ian@apathy:~$

[whitethorn]

You're using the wrong kind of quotes. There is ' and ` which is on the tilda button.

[jamesrl]

Pay attention to the type of quote. For me I need the tilted single quote. On my keyboard its on the same key as tilde. The backquote ` not ' or ", all of which have differences.

[jamesrl]

Basically the difference between the quotes can be seen by defining a variable and echoing.

Define your variable in the shell as:


export MY_VAR="ls -l"


Then type


export doubquotes="$MY_VAR"
echo $doubquotes
export singquotes='$MY_VAR'
echo $singquotes
export backquotes=`$MY_VAR`
echo $backquotes

the double quotes replaces the variable with its contents; the single quotes prints out the variable name; and the backquotes executes the command.

[jamesrl]

1) Okay, so it's a dash script. Got it. Is there an important difference?

In general bash has a little more features than sh/dash, and slightly different syntax. For a quick example, try


echo "\\n"

in both bash and sh. These small difference cause problems, when people specify /bin/sh but expect to use bash features. See:
https://wiki.ubuntu.com/DashAsBinSh