cloud engineer
If device is busy and you can’t umount it, try it with -l option (lazy unmount). Or you can force it.
# standard umount /mnt/data # lazy umount umount -l /mnt/data # force umount -f /mnt/data |
Lazy unmount is safer since it will detach immediately and clean up all references to the file system. Force is a bit more drastic.
If unable to login via SSH, check the /etc/ssh/sshd_config for AllowGroups.
AllowGroups root groupname |
It’s case sensitive.
Here’s how to run a shell script from your website. You’ll need 2 files.
Here’s the contents of foo.php. Wrap your output with ‘pre’ for better formatting.
<?php $output = shell_exec('/var/www/html/bar.sh 2>&1'); echo "$output"; |
Here’s the content of bar.sh. Output will be displayed on web page.
#!/bin/bash now="$(date +'%y%m%d')" echo $now aws s3 ls |
Here’s how to fix when phpinfo is displaying a blank page. The install is missing this php module.
apt install php libapache2-mod-php |
Restart after install.
service apache2 restart |
Here’s how to search for AWS Security Groups containing this IP Cidr.
aws ec2 describe-security-groups \ --filter Name=egress.ip-permission.cidr,Values='10.8.8.8/32' \ --query "SecurityGroups[*].{Name:GroupName}" \ --output text \ --profile default \ --region us-east-1 |
Search with ports.
aws ec2 describe-security-groups \ --filter Name=egress.ip-permission.cidr,Values='10.8.8.8/32' \ Name=egress.ip-permission.from-port,Values='22' \ Name=egress.ip-permission.to-port,Values='22' \ --query "SecurityGroups[*].{Name:GroupName}" \ --output text \ --profile default \ --region us-east-1 |
Query will only display the Security Group name.