Command Line

💭 What ? Imagine a web server that only starts when someone actually tries to access it. Or a database that spins up only when a query comes in: this is the magic of socket activation. The concept is not new, as old-school sysadmins may are used to see something like inetd or xinetd for on-demand service activation in the past. As some cool projects like cockpit have already started using this little-known feature, in this blog post we’ll see the basics and try to get familiarity with the tooling. ...

Why ? During my daily job I have sometimes to debug failed openqa test jobs. One of the testing mantra is to reproduce the issue and for that task the openqa community has developed some tooling. In practice, I often have some output like this one below from some job cloning operations: Cloning parents of sle-15-SP4-Server-DVD-Updates-x86_64-Build20250112-1-fips_ker_mode_gnome@64bit 1 job has been created: - sle-15-SP4-Server-DVD-Updates-x86_64-Build20250112-1-fips_ker_mode_gnome@64bit -> https://openqa.suse.de/tests/16425390 Cloning parents of sle-15-SP5-Server-DVD-Updates-x86_64-Build20250112-1-fips_ker_mode_gnome@64bit 1 job has been created: - sle-15-SP5-Server-DVD-Updates-x86_64-Build20250112-1-fips_ker_mode_gnome@64bit -> https://openqa.suse.de/tests/16425391 Cloning parents of sle-15-SP4-Server-DVD-Updates-x86_64-Build20250112-1-fips_ker_mode_gnome@64bit 1 job has been created: - sle-15-SP4-Server-DVD-Updates-x86_64-Build20250112-1-fips_ker_mode_gnome@64bit -> https://openqa.suse.de/tests/16425392 And when I want to monitor those jobs, I’d need to copy-paste all the job URLs and pass them as arguments to the cool openqa-mon utility which will show and notify me of the job status in the terminal. ...

A volte e’ necessario replicare le utenze con gli stessi parametri su piu’ server linux diversi. Perche’ farlo a mano ? Se sono tanti e’ un lavoro noioso e potremmo anche commettere degli errori. Ecco un semplice one-liner che fa il parsing di un file /etc/passwd e genera i corrispondenti comandi useradd awk -F: '{printf "useradd -m -u%s -g%s -d%s -s%s %s\n" , $3,$4,$6,$7,$1}' /etc/passwd Ovviamente l’output puo’ essere comodamente filtrato con grep, usato via copy&paste, inserito in uno script, eccetera… ...