curl grep script help

bilbonix · 06-10-2014, 06:01 PM

Can someon help me correct this please, run it until successful, five time max. The curl & grep work fine but adding it into a for loop I am unsure of

[CODE]for i in 1 2 3 4 5
do
if curl -s "http://www.blah.com" | grep -A 1 "Username: blah" | tail -n 2| cut -f2 -d " " | cut -f1 -d '<' > file.txt; then
break
sleep 10
fi
done/CODE]

metaschima · 06-10-2014, 06:57 PM

The main problem I see is that cut won't return a useful return value. I would split the command up. Grep will return a useful return value, so you could move the rest into the body of the if statement.

eklavya · 06-11-2014, 12:25 AM

where have you closed the loop?
where have you used i?
Are you sure you have found the text "Username: blah" without logging in the site?

pan64 · 06-11-2014, 12:37 AM

and the grep|tail|cut|cut chain can be replaced by a single awk script (which can also do the loop for you)

bilbonix · 06-11-2014, 04:08 AM

The currl grep bit works fine no need to change that as it writes the username and password to the file as specified.

I just want to loop the command upto five times until successful, specifically until the curl command is able to connect.

pan64 · 06-11-2014, 04:25 AM

the curl & grep chain does not work well because you have not get the return code back. That means the if actually check the return code of the last command (cut - and of course, it will never fail).
So combining that chain into one single command will allow you to handle this action much easier. The other way can be to check ${PIPESTATUS[*]}: http://aplawrence.com/Blog/B955.html

bilbonix · 06-11-2014, 06:55 AM

Okay, I see what you mean about the cut.

This works:

Code:

for i in 1 2 3 4 5 6 7 
do
        if curl -s "http://www.blah.com" | grep -A 1 "Username: blah"; then
           curl -s "http://www.blah.com" | grep -A 1 "Username: blah" | tail -n 2| cut -f2 -d " " | cut -f1 -d '<' > /opt/tmp/user.conf
		   logger -t "($(basename $0))" $$ blah password updated.... " $0${*:+ $*}."
           break
        else
            sleep 15
        fi
		
done