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David SankovskyFlag for Israel

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incorrect file reading in bash

Hi Experts.

I'm writing an automated Script in Bash, and I've got into a bit of a block...
I have a file called /scripts/resources/nodes,txt
The file currently hold only three lines:

10.5.17.3
10.5.17.4
10.5.17.5

and I have the following code:
#!/usr/bin/bash
filename="/scripts/resources/nginx_nodes_list.txt"
while read -r line
do
     NodeIP=$line
     echo "server $NodeIP {" >> /scripts/testloop.txt
done < "$filename"

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However, when I run the scripts and cat the resulting file, I only see 2 lines:

server 10.5.17.3 {
server 10.5.17.4 {
meaning the scipt skips the last one, any idea why?
Avatar of Terry Woods
Terry Woods
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When I set up a test doing the same thing, it worked.

Try double checking your input data just to make sure everything is actually as you say:
cat /scripts/resources/nodes,txt

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and your output (you may want to empty the output file first and rerun the script, since it's appending each time):
cat /scripts/testloop.txt

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ASKER CERTIFIED SOLUTION
Avatar of Dr. Klahn
Dr. Klahn

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try read without -r option.

Also, try to run script with bash -x and see what you get. It will show you each command while executing the script
What happen if you add one more line to the file?
David,

Your feedback is awaited.
You get this if the last line of the file does not have a carriage return (lots of things seem to do this, including some IDEs and Windows editors).

One thing you could try is:
grep . "$filename" | while read -r line
do
     NodeIP=$line
     echo "server $NodeIP {" >> /scripts/testloop.txt
done

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A drawback with this is that any variables set within the loop are no longer set outside the loop.  If, for example, you had a counter within the loop which you incremented for each line, that value would be lost when the loop finished.  If you need such a value, write it to a file within the loop, then read the file outside.
Avatar of David Sankovsky

ASKER

I had hidden characters... rookie mistake.. Thanks for the help