How can I compare two numbers in order to find the higher value in bash?-CodePudding

I have a small script in bash, I want to compare an old firmware version with a new one.

For example:

old fw: 2.9.7
new fw: 2.13.3

But when I run the script, it detects that 2.9 is higher than 2.13 and it doesn't update.

This is my script

#!/bin/bash
old=2.9.7
new=2.13.3

if [[ $old < $new ]];then
echo "Run the updates";else
echo "Does not need to update";fi

I get Does not need to update.

CodePudding user response：

With GNU sort and bash:

old=2.9.7; new=2.13.3

if [[ $(sort -V <(printf "%s\n%s\n" $old $new) | tail -n 1) == $new ]] ; then
  echo "newer"
else
  echo "older"
fi

From man sort:

-V: natural sort of (version) numbers within text

CodePudding user response：

In the case that new represents the latest version then you might just check for string equality:

old=2.9.7 new=2.13.3

if [[ "$old" != "$new" ]]
then
    echo "Run the updates"
else
    echo "Does not need to update"
fi