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…
To show excerpts instead of full post content on the homepage, category, tag, and author pages in WordPress Twenty Thirteen, you need to modify the theme’s template conditionals and add a custom excerpt filter. Edit content.php Open wp-content/themes/twentythirteen/content.php and locate the conditional that currently checks only for search results: <?php if ( is_search() ) :…
You’re seeing fatal errors because PHP has hit its default resource constraints: PHP Fatal error: Maximum execution time of 30 seconds exceeded PHP Fatal error: Allowed memory size of 268435456 bytes exhausted These limits exist to prevent runaway scripts from consuming server resources. Here’s how to increase them. Via php.ini (Global Configuration) The most reliable…
Several native options now exist for annotating PDFs directly on Linux, though each has trade-offs between features and ease of use. Native Linux Tools Okular is the most straightforward choice for basic annotations. It’s lightweight, fast, and saves markups directly into the PDF: sudo apt install okular okular document.pdf Okular supports highlighting, underlining, strikethrough, freehand…
Handling Ctrl-C gracefully in a Bash script is essential when you need to perform cleanup operations, save state, or notify users before exiting. The trap builtin makes this straightforward. Basic Trap Setup The fundamental approach uses the trap command to catch the INT signal (which Ctrl-C generates): trap ctrl_c INT function ctrl_c() { echo “Ctrl-C…
Spawning background processes in Bash is straightforward with the & operator, but there are several nuances depending on your use case. Basic approach The simplest method is appending & to your command: for i in $(cat ./all-hosts); do ssh “$i” “ifconfig | grep Link” & done Each & launches the process in the background and…
Scala runs on the JVM, so you need Java installed first. Install the default JDK with: sudo dnf install java-latest-openjdk java-latest-openjdk-devel On Fedora, this installs OpenJDK to /usr/lib/jvm/java-*-openjdk-* and symlinks it as /usr/lib/jvm/java. Verify the installation: java -version javac -version Install Scala Scala is available in the Fedora repository. Install it with: sudo dnf install…
When your distro’s package repositories lag behind, installing Scala directly from the official release is straightforward. This approach works on any Linux system with Java already installed. Prerequisites You’ll need a JDK installed. On most systems: # Debian/Ubuntu apt install default-jdk # RHEL/Fedora/CentOS dnf install java-17-openjdk-devel # Alpine apk add openjdk17 Verify your Java installation:…
Linux routing tables exist in kernel memory during runtime. To persist routes across reboots, you need to store them on disk and have them reloaded during system startup. The mechanism varies depending on your network management setup. systemd-networkd and netplan (modern systems) On contemporary distributions using systemd-networkd or netplan, define routes in YAML configuration files….
You can run OCaml scripts directly from the command line with a shebang, similar to bash or Python. This requires making the file executable and using the proper interpreter directive. Basic Script Setup Create a file with a .ml extension and add a shebang at the top: #!/usr/bin/env ocaml print_endline “Hello world!”;; Then make it…
The common claim that cin is significantly slower than scanf in C++ is partially true, but only when comparing default configurations. The reality is more nuanced. Why cin Can Be Slower by Default By default, C++ streams maintain synchronization with C stdio streams (stdin, stdout, stderr). This synchronization requires additional overhead because the library must…
To load and execute code from a source file in the OCaml interactive toplevel, use the #use directive: #use “file-name”;; This reads, compiles, and executes OCaml phrases from the specified file as if you’d typed them directly into the toplevel. Execution stops at the first error encountered. Common use cases Loading utility functions If you…
Managing OCaml packages effectively depends on your workflow and environment. The current standard is OPAM (OCaml Package Manager), which handles dependency resolution, version switching, and sandboxed environments. OPAM: The Standard Choice OPAM is the de facto package manager for OCaml and is maintained by the OCaml community. Install it using your system package manager or…
Which ones are good systems conferences? Top ones by ACM and USENIX: OSDI: https://www.usenix.org/conferences/byname/179 SOSP: http://sosp.org/ Other SIGOPS Events: http://www.sigops.org/conf-sponsored.html EuroSys: http://www.eurosys.org/ SoCC: http://www.socc2013.org/ (SoCC 2013) ASPLOS: http://www.sigplan.org/Conferences/ASPLOS/Main VEE: http://www.sigplan.org/vee.htm USENIX ATC: https://www.usenix.org/conferences/byname/131 NSDI: https://www.usenix.org/conferences/byname/178 IEEE Conferences: ICDCS: http://www.temple.edu/cis/icdcs2013/ (2013) IPDPS: http://www.ipdps.org/ Other related ones and workshops: HPCA: Search HPCA ConferenceSC: http://www.supercomp.org/IEEE CLUSTER: http://www.clustercomp.org/ HotCloud:…
OCaml’s int type size depends on your platform’s architecture. On 64-bit systems, int is 63 bits; on 32-bit systems, it’s 31 bits. This catches many people off guard when they test bitwise operations. Here’s why: OCaml uses one bit as a tag to distinguish integers from pointers at runtime (the least significant bit). So on…
OCaml provides robust FFI (Foreign Function Interface) capabilities for calling C code. This is essential when you need to use existing C libraries or write performance-critical sections in C. Using the Unix Module The simplest approach for Unix/Linux system calls is the built-in Unix module, which wraps common POSIX functions without requiring manual FFI binding….
Consistency models define the guarantees that a distributed system makes about the order and visibility of data modifications across nodes. Understanding these models is essential when designing systems, choosing databases, or debugging data anomalies in production. Strong Consistency Models Strict Consistency is the ideal but rarely achievable model. It guarantees that reads always reflect the…
Transactional memory (TM) is a synchronization mechanism that simplifies concurrent programming by allowing multiple threads to execute code atomically without explicit lock management. If you’re getting into this area, here are the best resources and practical approaches to build solid understanding. Foundational Reading The classic reference is still Transactional Memory by James R. Larus and…
GNOME can automatically restore your session—reopening all applications and windows that were running when you last logged out. This differs from autostart scripts, which launch specific programs on every login regardless of what was running before. Automatic Session Restoration To enable automatic session restoration in GNOME: Open Settings → General (or search “Session” in Activities)…
If you’re running Question2Answer and want to replace the default search with Google Custom Search without modifying your theme, a plugin is the cleanest approach. Setup Requirements Before implementing Google Custom Search, you’ll need: A Google account Google Custom Search Engine (CSE) created at cse.google.com Your CSE ID (cx parameter) Question2Answer 1.8+ installed and functioning…