Convert string into integer in bash script - “Leading Zero” number error

Question

In a text file, test.txt, I have the next information:

sl-gs5 desconnected Wed Oct 10 08:00:01 EDT 2012 1001

I want to extract the hour of

Answer 1

See ARITHMETIC EVALUATION in man bash:

Constants with a leading 0 are interpreted as octal numbers.

You can remove the leading zero by parameter expansion:

hour=${hour#0}

or force base-10 interpretation:

$((10#$hour + 1))