Link to home
Create AccountLog in
Avatar of David Sankovsky
David SankovskyFlag for Israel

asked on

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:

and I have the following code:
while read -r line
     echo "server $NodeIP {" >> /scripts/testloop.txt
done < "$filename"

Open in new window

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

server {
server {
meaning the scipt skips the last one, any idea why?
Avatar of Terry Woods
Terry Woods
Flag of New Zealand image

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

Open in new window

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

Open in new window

Avatar of Dr. Klahn
Dr. Klahn

Link to home
Create an account to see this answer
Signing up is free. No credit card required.
Create Account
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?

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
     echo "server $NodeIP {" >> /scripts/testloop.txt

Open in new window

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


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