[SOLVED] Simple script needed to detect OS

michaelk · 05-31-2017, 07:20 AM

Its not very pretty but simple.

Code:

ostype=$(lsb_release -d | grep CentOS)

If the string $ostype is empty then the OS is Ubuntu.

gkasica · 05-31-2017, 04:11 PM

OK I've come up with the below script and tested on CentOS with the indicated errors...I have NO idea what to do here to fix this my understanding is that is it shou;d be finding at least one "CenntOS" out there and firing the CentOS section...I've obviously commented out the patching and reboot for testing - taking down a server alot is sort of job limiting

#!/bin/bash
#
value=$( grep -ic "CentOS" /etc/*release* )
value1=$( grep -ic "Ubuntu" /etc/*release* )
#
# CentOS
#
if [ $value -ge 1 ]
then
echo "I found CerntOS"
# yum -y update
sleep 3
# reboot
#
# Ubuntu
#
elif [ $value1 -ge 1 ]
then
echo "I found Ubuntu"
#
# apt-get update
sleep 3
# apt-get -y dist-upgrade
sleep 3
# apt-get -y autoremove
sleep 3
# reboot
#
else
echo "Neither CentOS or Ubuntu Found"
#
fi

[root@stadmnwksdb01 ~]# cat ./ossupdate.sh
#!/bin/bash
#
value=$( grep -ic "CentOS" /etc/*release* )
value1=$( grep -ic "Ubuntu" /etc/*release* )
#
# CentOS
#
if [ $value -ge 1 ]
then
echo "I found CerntOS"
# yum -y update
sleep 3
# reboot
#
# Ubuntu
#
elif [ $value1 -ge 1 ]
then
echo "I found Ubuntu"
#
# apt-get update
sleep 3
# apt-get -y dist-upgrade
sleep 3
# apt-get -y autoremove
sleep 3
# reboot
#
else
echo "Neither CentOS or Ubuntu Found"
#
fi

[root@stadmnwksdb01 ~]# ./ossupdate.sh
./ossupdate.sh: line 8: [: too many arguments
./ossupdate.sh: line 17: [: too many arguments
Neither CentOS or Ubuntu Found

[root@stadmnwksdb01 ~]# cat /etc/*release*
CentOS release 6.3 (Final)
cat: /etc/lsb-release.d: Is a directory
CentOS release 6.3 (Final)
CentOS release 6.3 (Final)
cpe:/o:centos:linux:6:GA

michaelk · 05-31-2017, 04:20 PM

Did you see my previous post? The lsb_release command was suggested in post #2 and is available on both systems.

Code:

value=$(lsb_release -d | grep CentOS)
if [[ -z $value ]]; then
  echo "I found Ubuntu"
else
  echo "I found CentOS"
fi

astrogeek · 05-31-2017, 08:24 PM

Please place your code snippets inside [CODE]...[/CODE] tags for better readability. You may type those yourself or click the "#" button in the edit controls.

pan64 · 06-01-2017, 12:25 AM

I would suggest you to insert set -xv at the beginning of your script to see what's happening.
You will see:

Code:

$ grep -ic "Ubuntu" /etc/*release* 
/etc/lsb-release:2
/etc/os-release:6

this grep did not return a single number, therefore $value is not a number.
Also try www.shellcheck.net to fix other errors in your script.
(and also please use [code]here comes your code[/code] to keep formatting and make it more readable.

ondoho · 06-01-2017, 02:14 PM

critical commands can be prepended with an echo for testing:

Code:

echo sudo apt-get update

but...

Quote:

Originally Posted by gkasica

now the dirty way to do it just to let it fall through and fail on the systems that don't have the other OS update utilities but I'm trying to not do that.

i think this isn't such a bad solution at all.
with a bit of additional testing before executing the command, i think it's a pretty safe indicator whether yum or apt is installed.

michaelk · 06-01-2017, 02:48 PM

The OP marked it as solved so I assume the script is working now.

As a FYI it appears your if statement was trying to check the return status of grep but the contents of $value was the actual output. The return status is contained in the variable $?.