[SOLVED] How to filter shell output to only number with decimal?

Issue

I have CI/CD Config which required python version to be set to default by pyenv. I want to python2 -V output showed up with only, example, 2.7.18. But, rather than showing 2.7.18, it showing full text Python 2.7.18 .

But, when I use it in python3 python -V, it showed the correct & current python3 version (3.9.0).

I use this code to try showing numbers only : $(python -V | grep -Eo '[0-9]\.[0-9]\.[10-19]').

And to set default with pyenv : pyenv global $(python3 -V | grep -Eo '[0-9]\.[0-9]\.[10-19]') $(python -V | grep -Eo '[0-9]\.[0-9]\.[10-19]')

So pyenv $(python3 version) $(python2 version)

Here is the image :

Image of wrong output

Thanks!

Solution

A simple way would be to just replace the string Python with the emtpy string, if it exists.

Here a quick one-liner

python -V 2>&1| sed -e "s/Python//g" | xargs

That would print the python version, redirects stderr to stdout, replaces "Python" with "". Xargs without parameters returns the trimmed input string.

Answered By - stolzem