在bash中获得类似“ 310”的Linux内核版本？

Question

I create a script that I need the current kernel version in a specific way.

For example, if I use : 3.10.34-1-MANJARO I want to get only 310

Which is the best/easy way to do it ?

Answer 1

You could use awk :

awk -F. '{print $1$2}' <<< "3.10.34-1-MANJARO"

or cut :

cut -d. -f1-2 --output-delimiter='' <<< "3.10.34-1-MANJARO"

Answer 2

To complement @devnull's helpful answer with a bash-only solution, using bash's regex-matching operator, =~ :

ver=$([[ $(uname -r) =~ ^([0-9]+)\.([0-9]+) ]];
      echo "${BASH_REMATCH[1]}${BASH_REMATCH[2]}")

echo "$ver" # e.g., -> '310', if `uname -r` returned "3.10.34-1-MANJARO"

---

An alternative solution using bash parameter expansion:

Note : This will only work if the output from uname -r contains a - in the 3rd . -based component - this appears to the case for Linux distributions (but not, for instance, on OSX).

ver=$(uname -r)          # get kernel release version, e.g., "3.10.34-1-MANJARO"
ver="${ver%.*-*}"        # remove suffix starting with '.' and containing '-'
ver="${ver//.}"          # remove periods (a single `/` would do here)

echo "$ver" # e.g., -> '310'

Tip of the hat to @alvits, who points out that uname -r may have an additional . component describing the architecture - eg 3.8.13-16.2.1.el6uek.x86_64 .

Answer 3

A 'Bash only' solution:

declare -a TEMP2
TEMP1=$(uname --kernel-release)
TEMP2=(${TEMP1//[.-]/ })
VERSION=$(((${TEMP2[0]} * 100)\
    + ${TEMP2[1]}))
echo $VERSION

This will still work when the OP's version bumps up to something like 4.1