Arithmetic comparison in Shell Script
Hello,
I wrote a script to check the version of Firefox and update it if its older the 2.0.0.5.
It seems that -lt, -gt, or -eq does not look at anything after the first decimal. So, if my current version is 2.0.0.4, Firefox does not get updated.
The portion of code that is giving me a problem is below:
if [ $firefox_version -lt 2.0.0.5 ]
then
...
fi
So the question is, is there a way to do comparisons on numbers with decimals?
# 2
You could also sed out the dots, making '2.0.0.5' 2005 and '2.0.0.4' 2004, that would make the expression:
if [ 2004 -lt 2005]; then ...
which would work fine.
This would of course break with a future release of 2.2, since 22 is less than 2005, but you could fix that by adding a check which adds trailing zeros if the string is less than two characters, hence making version 2.2 appear as 2200..
This little while-statement would ensure that $firefox_version is always (at least) four digits long:
while [ `/bin/echo "${firefox_version}\c" |wc -m` -lt 4 ]; do
tmp="${firefox_version}0"
firefox_version=$tmp
done
Hmm.. sorry, i think i just got a bit carried away ;)
.7/M.
