When your HP printer runs out of paper mid-job on Linux, the print queue pauses and won’t resume automatically once you reload paper. You need to either clear the error state physically or use CUPS commands to resume printing. Physical Reset Method The quickest approach for most HP printers is to trigger the paper-detect sensor:…
The nl command is purpose-built for adding line numbers to text files: nl text-file By default, nl numbers all non-empty lines and skips blank lines. This behavior is controlled by the body section style, which defaults to t (text only). Common nl options Number all lines including blanks: nl -ba text-file Start numbering at a…
The lp command is the standard tool for printing from the Linux command line. It interfaces with CUPS (Common Unix Printing System), the printing backbone on virtually all modern Linux distributions. Basic Printing Send a file to your default printer: lp text-file.txt Specify a particular printer: lp -d printer-name text-file.txt List available printers and identify…
Bash doesn’t have a goto statement, and that’s intentional. The language is designed to encourage cleaner control flow patterns that are easier to debug and maintain. When you feel the urge to jump around in your script, there’s almost always a better approach. Functions and Early Return The cleanest pattern is extracting logic into functions…
When you have shared Makefiles included across multiple projects in different directory structures, relative includes break. If common.mk tries to include release.mk and both files are in a subdirectory like external/, the include fails because Make uses the current working directory, not the location of the including file. For example, this structure works fine: Makefile…
AddThis provides social sharing buttons for websites. If you’re using the AddThis Tweet button and want to add a via parameter (to attribute tweets to a specific Twitter account), here’s how to configure it. AddThis Tweet Button with via Parameter Modify the AddThis button configuration to include the tw:via attribute: <!– AddThis Tweet button with…
Gnuplot can output directly to EPS (Encapsulated PostScript) format, which is useful for including plots in LaTeX documents and other publishing workflows. Direct EPS Output The simplest approach is to set the terminal to postscript with the eps option before plotting: set terminal postscript eps enhanced mono “Helvetica” 14 set output “my-plot.eps” plot sin(x) This…
Several tools can convert .doc and .docx files to PDF from the command line. Here’s what works in practice. LibreOffice (most common approach) The standard command is: libreoffice –headless –convert-to pdf –outdir /path/to/output/ /path/to/file.docx This works well on systems with X11 available. However, on truly headless servers, –headless doesn’t fully suppress X11 requirements—LibreOffice will still…
Running your own Python installation on Dreamhost (or similar shared hosting) gives you control over the version, packages, and dependencies without relying on system-wide Python. This is especially useful when you need specific Python versions or packages the hosting provider doesn’t support. Why Use a Custom Python Installation Shared hosting environments typically ship with outdated…
Over time, internal and external links on your site inevitably break — pages get deleted, domains expire, content moves. Finding and fixing these broken links improves user experience and helps with SEO, since search engines penalize sites with dead links. Automated Checking Tools Several web-based tools can scan your site and report broken links: https://www.brokenlinkcheck.com/…
sbt (Scala Build Tool) isn’t available in the default Fedora repositories, though Scala itself is. Here’s how to install it properly. Using the Official Repository The most reliable approach is to add sbt’s official repository to your system. This gives you automatic updates and avoids manual RPM downloads. Create the repository configuration file: sudo tee…
Trailing spaces and tabs at the end of lines are common annoyances in source code and configuration files. They’re invisible, waste space, and can cause issues with certain tools or version control systems. Here’s how to remove them efficiently. Using sed The most straightforward approach with sed: sed ‘s/[[:space:]]*$//’ your_file > your_file.tmp && mv your_file.tmp…
If you have emails stuck in Evolution’s local directory structure that you want to move to an IMAP account via Thunderbird, you’ll need to convert them to a format Thunderbird can import, then push them to your mail server. Step 1: Prepare Your Evolution Mail Directory Evolution typically stores mail in a Maildir format with…
You sometimes need to know whether your shell is running inside screen or tmux. The most straightforward approach is checking the TERM environment variable. Using TERM When screen starts a shell, it sets TERM=screen by default: [user@host ~]$ echo $TERM screen Compare this to a normal terminal session: [user@host ~]$ echo $TERM xterm-256color The TERM…
Amazon’s Kindle Library web interface forces you to delete books one at a time through the UI. If you’ve accumulated hundreds of items, this becomes tedious. Here are practical approaches to bulk-delete from your Kindle Library. Browser Console Method The most straightforward approach uses your browser’s developer console to run deletion scripts directly against Amazon’s…
When you need to page through error output from a command, you’ll run into the issue that less only receives stdout by default. Error messages go to stderr (file descriptor 2), so they’ll still scroll past on your terminal while stdout gets paged. Basic approach: combine stderr with stdout make 2>&1 | less The 2>&1…
There are several reliable methods to generate random strings of a specific length in bash. The choice depends on your character set requirements and use case. Using tr with /dev/urandom The tr command combined with /dev/urandom is the most portable and straightforward approach: tr -dc “[:alpha:]” < /dev/urandom | head -c 10 This produces a…
Cron is a minimal execution environment. Unlike your interactive shell, cron runs with a stripped-down environment containing only a few variables like PATH, MAILTO, and SHELL. Any variables you’ve defined in your shell profile won’t be available unless you explicitly source them in your crontab entries. The Problem If your cron job depends on environment…
When you need to populate PDF forms with large datasets, manual entry becomes impractical. Scripting this process saves time and eliminates human error. Here’s how to automate PDF form filling using Python. Understanding PDF Form Filling PDF forms contain field names that can be programmatically populated. The process typically involves: Identifying field names in your…
Redis is an in-memory data structure store designed for speed and simplicity. Understanding its architecture and consistency guarantees is essential for deploying it correctly in production systems. Core Architecture Redis operates as a single-threaded, event-driven server that uses an in-memory data store with optional persistence. The single-threaded nature simplifies reasoning about concurrent access — all…