Here’s how to run a script with another user privilege. You can run this user with root.
su -c "/usr/bin/executable" -s /bin/sh username
Where the “username” is the username whom privilege you want to execute
Solving ‘kex protocol error: type 7’ error in scp and ssh
The message sometimes appear when transferring files using scp.
In order to solve this, you need to edit “/etc/sshd_config” file and change or add this line:
UsePrivilegeSeparation yes
Then restart OpenSSH server. This will solve the kex protocol error problem,
Find largest file in Linux server using “du”
Short on diskspace? You can use ‘du’ to find largest files in your linux server using ‘du’ tool.
du --total -sh /path/*
Additionally you can also include a ‘threshold’ parameter to list only file larger than the unit which you’ve specified, by using “-t” parameter.
Example, list files larger than 100MB
du --total -sh -t100M /path/*
You can use “M” for megabytes, “G” for gigabytes and “P” for Petabytes. Positive number denotes files must be at least the specified size. Negative number means the files must be at most the specified size.
Easily find duplicate files in Linux with fdupes
‘fdupes’ is a handy tool to find and list duplicates file in GNU/Linux or Unix-like operating system.
In Ubuntu you can install fdupes using apt command-line tool
apt -y install fdupes
Usage of fdupes is simple enough, just write:
fdupes -r /path/to/files/
The command will list duplicate files in the “/path/to/files”directory, which is a prime candidate for deletion.
Get Free cronjob from Cron-Job.org!
Cronjob or CRON is an important tool to perform automated / schedule task for web application.
Some shared hosting company may limit (or completely disable) the cron service functionality leading to some web application unable to perform periodic / automated task.
Luckily there’s website such as Cron-Job.org which offers free cron-job to those who aren’t able to obtain one.
The best thing about Cron-Job.org service, is they allow minute-by-minute cronjob execution for free!
Bonus: The folks at Cron-Job also releases the source code behind the service at GitHub!
How to Update Nmap scanner database
Nmap (or Network Mapper) is probably the most popular network mapper around. However if you are running a very stable long-term support server, there are chances that your nmap database installation isn’t keep up to that.
Updating Nmap database
Nmap detection database consists of these files:
- nmap-os-db
- nmap-mac-prefixes
- nmap-payloads
- nmap-protocols
- nmap-rpc
- nmap-service-probes
- nmap-services
What you need to do is to download these files from Nmap Github project page and copy it to /usr/share/nmap/ folder.
Alternatively, you can use this script ‘nmap-update.sh’ which I’ve created based on this gist.
Copy all the files to /usr/share/nmap/ once all of them have been downloaded.
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