How to extract only values greater than a threshold from a file?

With awk

awk -F: '{if($2>10)print$2}' <filename

Explanations

• -F: – sets the Field separator to :
• {if($2>10)print$2} – for each line, test whether the 2nd field is >10, if so print it
• <filename – let the shell open file filename, that's better than letting awk do that, see Stéphane Chazelas' answer on the topic

Example run

$ <filename awk -F: '{if($2>10)print$2}'
15.02
12.58

It's also possible to add spaces and put the pattern outside the brackets, so these are equal – thanks to Stefan for pointing that out:

awk -F: '{if($2>10)print$2}' <filename
awk -F: '{ if ( $2 > 10 ) print $2 }' <filename
awk -F: '$2>10{print$2}' <filename
awk -F: '$2 > 10 { print $2 }' <filename

With grep you'd have to work with regular expressions; e.g.

grep -E ':[^0-9]*[1-9][0-9][0-9]*\.' file | cut -d':' -f2

as with sed:

sed -n 's/.*:[^0-9]*\([1-9][0-9][0-9]*\..*\)/\1/p' file

But using RegEx on ordered data is error prone (in my experience) and difficult to read ;-).