![8vl3onvznkopxa6ny9995yrc4gw[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/8vl3onvznkopxa6ny9995yrc4gw1-550x230.jpg "Awk & sed Snippets for SysAdmins")
Books have been written on the subject of awk and sed. Here’s a small sample of commands I put together over the years that are useful for everyday system administration tasks. Most of these tasks …
Read the full story »![8vl3onvznkopxa6ny9995yrc4gw[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/8vl3onvznkopxa6ny9995yrc4gw1-100x65.jpg "Awk & sed Snippets for SysAdmins")
![9dwz62kvm0gtjya9kwb7pawtk9y[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/9dwz62kvm0gtjya9kwb7pawtk9y1-100x65.jpg "Finding Duplicate Photos")
![5o2y78yvwlg2lfep7d8fnznsnr3[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/5o2y78yvwlg2lfep7d8fnznsnr31-100x65.jpg "Collatz Conjecture in Bash")
![e4126w5dkl69jw9cm2xj39j8pba[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/e4126w5dkl69jw9cm2xj39j8pba1-100x65.jpg "Simple Math from Bash Command Line")
![zxulfg358ydpeyelfjppawbkxhr[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/zxulfg358ydpeyelfjppawbkxhr1-100x65.jpg "Focus Stacking with Lightroom and Photoshop")
![9yap7otat457ctjm63g78ann8mv[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/9yap7otat457ctjm63g78ann8mv1-100x65.jpg "Peculiar Linux Command-Line Tools")
![tq9mhhd5xy2q0kto2j1785n6odv[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/tq9mhhd5xy2q0kto2j1785n6odv1-100x65.jpg "NFS I/O Stats with Logging")
![4ucne6vs8m7hqdl0el9ddqd1sql[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/4ucne6vs8m7hqdl0el9ddqd1sql1-100x65.jpg "Inventorying NFS Mounts and Mount Options")
Commands & Shells, Featured »
Awk & sed Snippets for SysAdmins
![8vl3onvznkopxa6ny9995yrc4gw[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/8vl3onvznkopxa6ny9995yrc4gw1-150x150.jpg "Awk & sed Snippets for SysAdmins")
Books have been written on the subject of awk and sed. Here’s a small sample of commands I put together over the years that are useful for everyday system administration tasks. Most of these tasks involve reformatting strings and files, which is why I decided to bundle tr, cut, and paste into this mess.
Synology NAS Hacks
![rhd3hj6zvnqeth7qo8em0alduj0[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/rhd3hj6zvnqeth7qo8em0alduj01-80x80.jpg "Synology NAS Hacks")
I’ve been using various Synology NAS devices for many years now, and they’re great. Well, almost. There are a few rough spots that don’t thrill me. These consumer-grade devices are designed to be difficult to …
Finding Duplicate Photos
![9dwz62kvm0gtjya9kwb7pawtk9y[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/9dwz62kvm0gtjya9kwb7pawtk9y1-80x80.jpg "Finding Duplicate Photos")
Being a shutterbug and a digital hoarder can get expensive. A couple of days ago, my
TerraMaster D5-300 5-bay DAS crashed. Again. This time it was the power supply. I replaced it only to discover that …
Collatz Conjecture in Bash
![5o2y78yvwlg2lfep7d8fnznsnr3[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/5o2y78yvwlg2lfep7d8fnznsnr31-80x80.jpg "Collatz Conjecture in Bash")
The Collatz conjecture is a math problem from the mid-1930s. It involves an algorithm that starts with any positive integer, and then each following number is made by taking the previous number and changing it. …
Simple Math from Bash Command Line
![e4126w5dkl69jw9cm2xj39j8pba[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/e4126w5dkl69jw9cm2xj39j8pba1-80x80.jpg "Simple Math from Bash Command Line")
Chances are, most shell scripts you write will require some math operations, even if it’s something as simple as incrementing a variable inside of a loop. As with everything else in Linux, there are multiple …
Focus Stacking with Lightroom and Photoshop
![zxulfg358ydpeyelfjppawbkxhr[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/zxulfg358ydpeyelfjppawbkxhr1-80x80.jpg "Focus Stacking with Lightroom and Photoshop")
Not the usual topic for this blog and not the most comprehensive guide on the subject out there, but here I go anyway. Focus stacking combines multiple photos taken at different focal distances into an …
Generating Honeypot Data Structure
![on7avnij18ozm2jvppgdny2lhlv[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/on7avnij18ozm2jvppgdny2lhlv1-80x80.jpg "Generating Honeypot Data Structure")
I’ve been fiddling with my inotifywatch scripts to make a better “early-warning” system for ransomware detection and realized I needed a more realistic honeypot data structure. Ransomware is getting more clever and is no longer …
Peculiar Linux Command-Line Tools
![9yap7otat457ctjm63g78ann8mv[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/9yap7otat457ctjm63g78ann8mv1-80x80.jpg "Peculiar Linux Command-Line Tools")
Some Linux CLI commands I type every day, probably hundreds of times. Others – on a rare occasion. But there’s a category of truly esoteric utilities tailor-made for some singular and often exotic purpose. I …
NFS I/O Stats with Logging
![tq9mhhd5xy2q0kto2j1785n6odv[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/tq9mhhd5xy2q0kto2j1785n6odv1-80x80.jpg "NFS I/O Stats with Logging")
The nfsiostat is an excellent tool for analyzing NFS performance. The only major problem with this utility is that it’s designed to be used interactively. It does not have logging or timestamping capabilities. I needed …
Inventorying NFS Mounts and Mount Options
![4ucne6vs8m7hqdl0el9ddqd1sql[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/4ucne6vs8m7hqdl0el9ddqd1sql1-80x80.jpg "Inventorying NFS Mounts and Mount Options")
As time goes by, NFS mounts multiply like rabbits. Added by many different people over the years, these entries present a dizzying variety of mount options – most are a copy-paste job that makes little …
Automatic File Backups in VIM
![bqlpzjqba7fn1jtghunz0z1vv5d[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/bqlpzjqba7fn1jtghunz0z1vv5d1-80x80.jpg "Automatic File Backups in VIM")
Having to undo stupid changes to config files is an unfortunate side effect of too few sysadmins supporting too many servers. The VIM editor has some built-in file backup options. However, I find these options …
Joining Text Files and Data Columns
![p65q1znipa66jngo3jjvbnmb7s7-scaled[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/p65q1znipa66jngo3jjvbnmb7s7-scaled1-80x80.jpg "Joining Text Files and Data Columns")
When working with application logs and other text files, it is often useful to view the contents of different source files side-by-side. Here we will take a quick look at various command-line methods for joining …
Convert Color Text to Images in Bash
![uw4wrbh91igtkstbw6zr43yc5my[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/uw4wrbh91igtkstbw6zr43yc5my1-80x80.jpg "Convert Color Text to Images in Bash")
The textmg is a cool little CLI tool written by jiro4989 – a systems engineer from Japan – that allows you to convert the color output in a terminal window to an image file. I …
Solving Crossword Puzzles from CLI
![jddujk6sil1frr05tgusp596m0x[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/jddujk6sil1frr05tgusp596m0x1-80x80.jpg "Solving Crossword Puzzles from CLI")
Linux command-line tools provide access to a wealth of dictionaries, encyclopedias, thesauri, directories, and other reference sources. Learning to use these tools is a worthwhile endeavor even if solving crossword puzzles is not your favorite …
Productivity Shortcuts for .bashrc
![q3rkytdeesvavynm5bf9l8ejk6m[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/q3rkytdeesvavynm5bf9l8ejk6m1-80x80.jpg "Productivity Shortcuts for .bashrc")
Some of the useful (more or less) aliases and functions for the .bashrc file to make your life a little easier and delay the onset of carpal tunnel syndrome.
Decision Making Using Python TOPSIS
![96wed5sso8yxby9c0qj83cnkh6s[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/96wed5sso8yxby9c0qj83cnkh6s1-80x80.jpg "Decision Making Using Python TOPSIS")
In a nutshell, TOPSIS – the Technique for Order of Preference by Similarity to Ideal Solution – seeks out one of many options that is the closest to the ideal option while at the same …
Using Variables in Bash
![7svf2cvkbbkpa19u2ja8d98dnt8[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/7svf2cvkbbkpa19u2ja8d98dnt81-80x80.jpg "Using Variables in Bash")
A few quick tips on using variables in your Bash scripts. Nothing fancy here, just good practices that we often overlook.
WordPress: Post-processing of the image failed
![ytioq398kc1wnvvz95uixhcn5ii[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/ytioq398kc1wnvvz95uixhcn5ii1-80x80.jpg "WordPress: Post-processing of the image failed")
This particular WordPress issue appeared with version 5.3 and is refusing to go away. However, the problem here is not with WordPress but with the Apache ModSecurity. The particular ModSecurity rule in question is 200003 …
Clone Raspberry Pi SD to Larger Card
![kfji8o9kkwlt04vbdlf0jbczy9q[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/kfji8o9kkwlt04vbdlf0jbczy9q1-80x80.jpg "Clone Raspberry Pi SD to Larger Card")
This is more of a note to myself: every time I need to clone the RPi card, I end up googling things for an hour. The process is two-fold: clone the SD and resize the …
Laziness vs Phishing
![43v0r4nyow1rbpxrr6gunkcbfcj[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/10/43v0r4nyow1rbpxrr6gunkcbfcj1-80x80.jpg "Laziness vs Phishing")
Here’s an interesting article detailing the methods scammers use to steal your one-time passwords for Coinbase.
A Wrapper Script for unrar
![53wmyx6na9379un1mmku8ibq6x6-2[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/53wmyx6na9379un1mmku8ibq6x6-21-80x80.jpg "A Wrapper Script for unrar")
Just a straightforward wrapper script for the unrar command that allows extracting specified filetypes from multipart archives while utilizing all available CPU cores.
Convert XLSX to a MySQL Table
![7auipjfjec4veay7sa4hrw32xzg[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/7auipjfjec4veay7sa4hrw32xzg1-80x80.jpg "Convert XLSX to a MySQL Table")
Some people find it hard to let go of Excel even when the situation is ripe for a database. And so dozens of different versions of the same spreadsheet edited by many people are floating …
Generating IP Whitelists
![sonlxanvz0en50ijq03cedkaz2e[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/sonlxanvz0en50ijq03cedkaz2e1-80x80.jpg "Generating IP Whitelists")
I have several scripts that scan various log files for signs of suspicious activity and block the offending IPs on my Web servers – pretty standard stuff. The trick, of course, is not to block …
Commands & Shells »
Plundering Facebook Photo Albums
![wyryr1sn52gntzn65v4fpz5lc6v[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/wyryr1sn52gntzn65v4fpz5lc6v1-80x80.jpg "Plundering Facebook Photo Albums")
Let’s imagine you need to download all the photos in a Facebook photo album. It can be a public album, a friend’s, or even your own. Sure, you can do this manually, but you probably …
Scraping a Web Page in Bash
![clfud46mxf2t5zph2l04zlpgl1d[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/clfud46mxf2t5zph2l04zlpgl1d1-80x80.jpg "Scraping a Web Page in Bash")
Just a scripting exercise because I need to do something important, but I am procrastinating. The idea is simple: grab some URL with text containing somewhat structured data and convert it into a spreadsheet. I …
Applications »
Processing Videos with ffmpeg and Lightroom
![DSCF5361[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2020/10/DSCF53611-80x80.jpg "Processing Videos with ffmpeg and Lightroom")
On occasion I wondered how to apply advanced photo filters to my lackluster GoPro and drone videos. You know, not the basic exposure/contrast/saturation or the cheesy special effects you find in video editors, but something …
Searching Twitter
![Cat-Devouring-A-Bird-Pablo-Picasso[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2020/10/Cat-Devouring-A-Bird-Pablo-Picasso1-80x80.jpg "Searching Twitter")
Here are just a few hopefully useful tips for searching Twitter to get more relevant results and buy cheap twitter followers.
Data »
Scraping a Web Page in Bash
Just a scripting exercise because I need to do something important, but I am procrastinating. The idea is simple: grab some URL with text containing somewhat structured data and convert it into a spreadsheet. I …
Generating Random Text Files for Testing
![91ebozy1e3b138waujy28agrngy[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/91ebozy1e3b138waujy28agrngy1-80x80.jpg "Generating Random Text Files for Testing")
Sometimes you need dummy folder structures populated with random data for testing your various scripts and processes – backups, file transfers, encryption, compression, etc. Every time I need something like this, I end up writing …
Monitoring »
Finding Cron Jobs
![iwoau71okwxqh4jv3k4ook32qps[1]](https://i2.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/iwoau71okwxqh4jv3k4ook32qps1-80x80.jpg "Finding Cron Jobs")
Cron is an indispensable tool for system administration. The difficulties in working with cron in a large environment stem from its decentralized nature. Cron jobs multiply like rabbits, and keeping track of them is not …
Understanding Memory Utilization in Linux
![5gtysva4wkc8mzc1k3e66vaycxx[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2021/08/5gtysva4wkc8mzc1k3e66vaycxx1-80x80.jpg "Understanding Memory Utilization in Linux")
This is a depressing – and all-too-common – scenario: a user runs the free command and opens a support case because he sees zero “free” memory on the server.
Networking »
Validating HTTPS Cache Peers for Squid
![sy2zeb1vp2h8itlxfbbylw0jrm0[1]](https://i0.wp.com/www.krazyworks.com/wp-content/uploads/2019/12/sy2zeb1vp2h8itlxfbbylw0jrm01-80x80.jpg "Validating HTTPS Cache Peers for Squid")
I have a squid proxy server that uses a long list of authenticated cache peers in a round-robin configuration. The process looks something like this:
Verifying SNMP Connectivity on Multiple Hosts
![Photo-2019-10-07-14-39-03_0266[1]](https://i1.wp.com/www.krazyworks.com/wp-content/uploads/2019/11/Photo-2019-10-07-14-39-03_02661-80x80.jpg "Verifying SNMP Connectivity on Multiple Hosts")
I needed to check if SNMP was accessible on whatever live servers that existed in a particular subnet. Here’s a quick script to do this.
Editor
Igor
Sr. Unix SysAdmin with twenty years experience supporting Solaris, HP-UX, AIX, IRIX, and Linux servers in a large distributed environment.
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