CODEWITHSUNDEEP
linuxbash
user3064931
user3064931

Reputation: 129

Get linux kernel version like this "310" in bash?

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 ?

Upvotes: 1

Views: 1284

Answers (3)

sedwards
sedwards

Reputation: 24

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

Upvotes: 0

mklement0
mklement0

Reputation: 437052

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 - e.g. 3.8.13-16.2.1.el6uek.x86_64.

Upvotes: 2

devnull
devnull

Reputation: 123448

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"

Upvotes: 4

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