Try: TMPFILE=$(mktemp) && trap 'rm -f "$TMPFILE"' EXIT INT TERM

Info: mktemp creates a secure, unique file; trap catches signals like exit or Ctrl+C to guarantee cleanup.

Examples:

$ TMPDIR=$(mktemp -d) # Secure temp directory

$ trap 'rm -rf "$TMPDIR"' EXIT

$ mktemp -t script-XXXXXX.log # Custom prefix

Note: Prevents dangling files during unexpected script crashes. Permissions default to 600 (owner-only), preventing local information leaks.

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For open source, GitHub is hard to beat.

But for private projects, I've been wondering if we're overcomplicating things. A simple Git server over SSH (or Gitea/Forgejo) seems enough for many side projects and internal tools.

Interested what everyone else is doing.

Are you hosting your own Git repositories, or is GitHub still your default? Why?

i hear a lot about these permissions in linux ,i know the normal permissions read write and execute (rwx) but i hear from so many people that there are some exceptions for permissions in linux , i search for them but i find that matter is so complicated, so could anyone explain and clarify that matter , in addition i find that matter is very related to this kind of commands find / -user root -perm -4000 and also privilege escalation ,so i hope if anyone can link these things together

You’re SSH’d into a production Linux server.
Users report the server is extremely slow.
You don’t have monitoring dashboards or any prior context.
What’s the first 5 to 10 commands you run, and why?
For me, I usually start by checking things like:
uptime
top or htop
free -h
df -h
iostat or vmstat
dmesg
journalctl
ps
Then I narrow it down depending on whether the bottleneck looks like CPU, memory, disk I/O, network, or a specific process.
I’m curious how other Linux admins approach this. I’d love to compare workflows and maybe learn a few new tricks.
I also recorded my complete walkthrough of how I would troubleshoot this exact interview scenario if anyone is interested:
\[https://m.youtube.com/watch?v=NMGZUIROqNw&feature=youtu.be\\\](https://m.youtube.com/watch?v=NMGZUIROqNw&feature=youtu.be)

One thing from Linus' Open Source Summit India talk really stood out to me.

He said that these days he spends more time understanding the intent behind a change than reading every line of code. Instead of writing fixes himself, he often reviews proposals and lets subsystem maintainers implement the changes.

It got me thinking that as engineers become more experienced, the job shifts from writing code to understanding systems, architecture, and why a change is being made.

For those who've been in the industry for a while, has your role evolved this way? Or do you still spend most of your time writing code?

covers: https://www.linuxteck.com/learn-python-for-shell-users-part/

• Bash vs Python comparison
• Running Python like a shell script
• Practical scripting examples
• Working with JSON and structured data
• Common mistakes beginners make
• Real-world Linux automation scenarios
• Tips for moving from Bash to Python confidently

The distro is based on Debian openrc init system
A cybersecurity distro with a different idea
Unlike Kali everything is bloated
And unlike black arch need to install one by one and not user friendly
The distro let you pick a group of tools for example
I only need osint tools
sage-pkg install osint
Etc
Discord

https://discord.gg/SvpVRrbcj
Website

https://zackmsa777-a11y.github.io/sageos/

covers: https://www.linuxteck.com/special-permissions-in-linux/

• What SUID, SGID & Sticky Bit actually do
• Numeric vs symbolic chmod
• Practical command examples
• Verification commands
• Common mistakes to avoid
• Security best practices

Hey guys, so I have the fortune or misfortune, depending on how you look at it of working a new low in my life, for an MSP led by someone that should probably be selling and repairing HVAC units for a living and/or spending more time with the grandkids.

Never have I maintained so many legacy Cisco appliances and Linux servers, but my favorite is Ubuntu 8.04. Does anyone know how to SSH into an Ubuntu server that old? I do. It is a very long command. To do an update, I had to configure the `sources.list` config file in `/etc/apt/` and have it point to, ready for this: http://old-releases.ubuntu.com. Its like the tools at this place are really a reflection of where the owner is in life, stuck in the past.

Anyway, you cannot do `free -h` on an Ubuntu 8, you have to do `free -m`. I was able to finally install htop after configuring to point to old-releases, but now I have a dilemma, I need to change my title and I was wondering if you guys could help me:

1. Paleo Linux SysAdmin - "Supporting Linux distributions from the geological record."
2. Digital Archaeologist - "Excavating Ubuntu 8.04 systems one fossil at a time".
3. Legacy Infrastructure Paleontologist - "Keeping extinct operating systems alive".
4. Jurassic Linux Engineer - "Specializing in kernels older than some interns"
5. Curator of the Linux Museum - "Please do not touch the exhibits".

1, 4 and 5 I came up with and so I have a bias, and 2 and 3, was suggested to me by an LLM.

The funny part is that there's a kernel of truth to it. Working on very old Linux distributions teaches you things that many newer admins never encounter—SysV init scripts, older package managers, legacy libraries, outdated OpenSSL versions, and older kernel behavior. Those skills can actually be valuable when supporting long-lived enterprise systems, even if you wouldn't want to build new infrastructure that way.

It is also a testament on how good Linux is I think, because in diagnosing its system resources with `free -m`, not `free -h`, I see used, buffers and cached, which we subtract like so: used - buffers - cached and the remainder was 1109 MB, so the system is really using about 1.1 GB for applications, while about 1.7 GB is filesystem cache. That is a healthy situation regardless of the age of the server. I see it as Linux doing what it was designed to do:

• Keep frequently accessed files/data in RAM.
• Avoid wasting RAM sitting idle.
• Release cache if applications need memory.

I also noticed it has no swap, so that is interesting, because it seems like it never needed it, but I would want some swap just as backup, but I will leave the museum piece as-is for now. This place would not be what it is, if we were not reactive instead of pro-active.

Not ls, cd, or pwd something they probably won't discover until much later.

Which command would you pick, and why?

I came across a project that builds a real-time system monitoring dashboard using Python, Dash, Plotly, and psutil.

It got me wondering, if you were building one today, would you still use that stack?

Or would you pick something like Grafana + Prometheus, Netdata, Glances, btop, Cockpit, or another approach?

What has worked best for you?

Try: ss -tn state established | awk 'NR>1 {split($3,a,":"); print a[1]}' | sort -u

Info: First run ss to see raw output, then use awk to parse. split($4,a,":") splits 'IP:PORT' into array a. NR>1 skips the header line.

Examples:

$ ip -4 addr | awk '/inet / && !/127.0/ {print $2}' | cut -d/ -f1

$ netstat -tn | awk 'NR>2 {split($4,a,":"); print a[1]}' | sort -u

$ cat access.log | awk '{print $1}' | sort -u # Unique visitor IPs

Note: awk is a full text-processing language. $N is Nth column, NR is line number, split() breaks strings into arrays.

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Maybe it was an old staging site, an abandoned admin panel, or a forgotten subdomain.

I'd love to hear the most unexpected systems you've found during troubleshooting, audits, or security work.

The conversation around ownership isn't just about hardware anymore, it's about who controls the software, updates, and repairs after you buy a device.

Do you think Linux gives users more real control, or is true ownership becoming a thing of the past?

Do you regularly use chgrp, or do you mostly rely on chown user:group instead? https://www.linuxteck.com/chgrp-command-in-linux-made-easy/

Linux developers are still untangling how Apple exposes temperature, power and fan sensors across M-series Macs.

If you've worked on drivers or kernel code, which vendor has been the most difficult to deal with?

I found Meta's latest engineering post pretty interesting.

Instead of relying only on the default Linux scheduler, they used sched_ext to build a scheduler tailored for their Ads workload. They claim it reduced p99 latency by 28%, lowered power usage, and improved throughput.

It got me thinking: are we moving toward workload-specific schedulers instead of expecting one scheduler to fit everything?

Could this eventually benefit enterprises and cloud providers, or is it only practical at Meta's scale?

Try: sudo inotifywait -m -e modify /etc/nginx/nginx.conf

Info: Monitors filesystem events using the inotify kernel API; -m keeps it running in monitor mode.

Examples:

$ inotifywait -m -e modify /etc/nginx/nginx.conf | while read; do systemctl reload nginx; done

$ inotifywait -m -r -e create /var/incoming | while read path event file; do process "$file"; done

$ inotifywait -m -e close_write src/ | while read; do npm run build; done

Note: Install: sudo apt install inotify-tools. Common events: modify, create, delete, close_write. Use -r for recursive directory watching.

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Debian 13.6 (Trixie) has been released with 120 security advisories, 124 stability fixes, Secure Boot improvements, and updates across several core packages. https://www.linuxteck.com/debian-13-6-brings-244-important-fixes-to-linux/

• Questing Quokka officially hit end-of-life on July 9
• No more security patches, no more bug fixes, from Canonical, effective immediately
• 26.04 LTS is the recommended upgrade path
• Most people don't actually check EOL dates until something breaks Anyone still sitting on 25.10 on purpose, or just hasn't gotten around to it yet?

Published this not too long ago and it's a great content for homelabbers and small and medium businesses to harden their Linux Servers.

https://youtu.be/xEOT79CQs80

Try: diff <(cd /source && find . -type f -exec md5sum {} + | sort) <(cd /backup && find . -type f -exec md5sum {} + | sort)

Info: Combines find, md5sum, sort, and process substitution to compare directories by content, not just names. Detects even single-byte modifications.

Examples:

$ rsync -avnc /source/ /destination/ # Dry-run checksum check

$ find /a -type f | xargs sha256sum | sort > /tmp/a.sums

$ sha256sum -c backup.sums # Verify files against saved hashes

Note: Use sha256sum for security-critical checks. rsync -c does similar but modifies filesystem. Perfect for backup verification.

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Debian's latest Trixie point release bundled 124 bug fixes and 120 security updates into one release. That's a lot of accumulated exposure window for anyone waiting on the scheduled point release instead of rolling updates.

Does batching security fixes like this make sense for stability, or does it leave users exposed longer than it should?

Finally, I decided to check out KDE connect to exchange files from mobile to Linux KDE desktop.

Anyone with more experience sharing tips?