If a project consists of multiple git repositories I’d like to see if I forgot to create a commit in one of them at the end of a development day.
This little bash script traverses all directories with a .git directory and checks with a ‘git status’ what the status of that git repository is.
Handy! I’d use it, if it were me!
for x in $(find . -type d -name ".git"); do pushd $(dirname $x); pwd; git status; popd; doneFor an application in C I wanted to know if a provided path is a mountpoint, so that a drive is mounted at that path.
With the help of the mtab file, which include all the mounts, we can iterate over that list and see if provided path is actually a mount point.
See ‘cat /etc/mtab’ to see the content of this file.
#include <mntent.h>
#include <stdio.h>
#include <string.h>
static bool path_is_mountpoint( CHAR* path )
{
// Return if path is mountpoint (true), or not (false)
BOOLEAN mounted = false;
// Open mtab file.
FILE * mtab = setmntent ("/etc/mtab", "r");
struct mntent* mountpoint = nullptr;
// Return directly if we could not open the file.
if ( mtab == nullptr) return mounted;
// Iterate over each entry in mtab list, and check if path is present
while ( ( mountpoint = getmntent(mtab) ) != nullptr) {
if ( (mountpoint->mnt_fsname != nullptr ) &&
(strcmp(mountpoint->mnt_fsname, path ) == 0) )
{
// We found path in mtab, so path is mountpoint.
// Stop iterating.
mounted = true;
break;
}
}
endmntent (mtab);
printf("path: %s, Is mountpoint: %d", path, mounted);
return mounted;
}When building large projects with Yocto/Bitbake I encountered hangups of my host OS due to lack of RAM space.
The solution to that was creating a SWAP partition, which actually allocates space on a SSD (preferably) or a HDD. Note that a HDD and SSD are always slower than RAM, but better than having hangups.
How to create a swapfile on Ubuntu 18.04 (may work on other distros as well). Replace <user> with your local user (echo $USER).
# bs=1G and count=4 -> 4GB swapfile
$ dd if=/dev/zero of=/home/<user>/swapfile bs=1G count=42. Set correct permission on the swapfile
$ sudo chmod 600 /home/<user>/swapfile3. Make ‘swapfile’ usable as swap
$ sudo mkswap /home/<user>/swapfile4. Tell the OS to use the swapfile
$ sudo swapon /home/<user>/swapfileIn principle you are done. The OS is using your swapfile. However it is not acitivated on a restart of your OS. To fix that we have to add it to the fstab file.
5. Add the following line to the /etc/fstab
/home/<user>/swapfile none swap sw 0 0Check with “top”, “htop”, or even “bashtop” your new physical memory size!
Finally, you’d like not to use the swapfile if it is not necessary. You can specify the “swappiness” for that.
# 0 = disable swap, 100 = swap as much as possible
$ sysctl vm.swappiness=10Sources:
[1] https://help.ubuntu.com/community/SwapFaq
Of course nobody should be able to login to your server. But if someone finds a way to do it, don’t you want to know it?
I am running an Ubuntu Server that uses motd to welcome logged in users. Therefore I am using motd to execute a script for me once a user logged in.
I extracted the details of the just logged in user from /var/log/auth.log, and uses the IP address and a resolver (ipapi.co in my case) to resolve the IP address to a location.
I am using a Telegram Chat with my own Telegram bot to notify me. I might write a small blogpost about my Telegram bot in the future.
Place the script in a file, make it executable, and place it in /etc/update-motd.d/. For example:
$ touch /etc/update-motd/01-notify-me.sh
$ chmod +x /etc/update-motd/01-notify-me.sh
$ vi /etc/update-motd/01-notify-me.sh # Add script And the actual script:
#!/bin/bash
_loginDetails=$(grep "Accepted" /var/log/auth.log | tail -n 1)
_IP=$(echo $_loginDetails | awk '{print $11}')
_LOCATION=$(curl https://ipapi.co/${_IP}/json/ | jq .city -r)
_METHOD=$(echo $_loginDetails | awk '{print $7}')
_WHO=$(echo $_loginDetails | awk '{print $4}')
message="[SSH LOGIN] => ${_WHO} from ${_LOCATION}, IP: ${_IP}, AUTH: ${_METHOD}"
curl -s -X POST https://api.telegram.org/<bot_token>/sendMessage -d chat_id=<chat_id> -d text="${message}"Additional security measures should be taken, for example:
© 2025 Roholt
Thema door Anders Norén — Omhoog ↑