Getting the Highest Temperature from All Sensors Monitoring server temperatures is essential for preventing hardware damage and maintaining system stability. Linux provides several tools to query thermal sensors and identify which components are running hot. Using lm-sensors The most reliable approach is lm-sensors, a userspace tool that reads temperature data from kernel drivers: # Install…
EncFS on Android: Current State and Alternatives EncFS is a FUSE-based encrypted overlay filesystem that was once popular for transparent file encryption. However, its use on Android has become impractical due to Android’s security architecture. Here’s what you need to know in 2026. Why EncFS Doesn’t Work Well on Android Anymore Android’s evolution has made…
Getting File Modification Time on Linux The modification time (mtime) indicates when a file’s content was last changed. This is critical for scripting, backups, logging, and dependency tracking in builds. Using stat The stat command is the most reliable tool for retrieving mtime programmatically: stat -c %Y filename This outputs the Unix timestamp (seconds since…
Checking Previous Boot Logs with systemd-journald The command journalctl -b -1 should show the previous boot’s journal, but on many systems it returns: Failed to look up boot -1: No such boot ID in journal This happens because persistent journal storage isn’t enabled by default. Without it, journald only keeps logs in volatile memory (/run/log/journal),…
Finding a hostname from an IP in /etc/hosts on Linux When you need to reverse-lookup an IP address against your local /etc/hosts file, several tools can help. This is different from a full DNS reverse lookup — you’re checking only against the static mappings on your local system. Why this matters By default, most hostname…
Reloading fstab Changes with systemd When you modify /etc/fstab, systemd doesn’t automatically pick up the changes. You need to explicitly tell systemd to reload its configuration and apply the new mount points. The Basic Reload To force systemd to recognize changes in /etc/fstab, run: sudo systemctl daemon-reload This tells systemd to re-read all unit files…
Printing to STDOUT and STDERR in Bash Understanding file descriptors is fundamental to shell scripting. By default, your shell has three standard streams: STDOUT (FD 1): Standard output, where commands print results STDERR (FD 2): Standard error, where commands print errors and diagnostics STDIN (FD 0): Standard input, where commands read data Basic Output Print…
Getting the Parent Process ID in Python To get the parent process ID (PPID) of the running process, use the os.getppid() function: import os ppid = os.getppid() print(f”Parent Process ID: {ppid}”) This returns the process ID of the parent process as an integer. On Unix-like systems, this is straightforward. On Windows, the behavior is consistent…
Built-in Debugging Flags Bash has several native flags that help you trace and validate script execution before and during runtime. Trace mode (-x): Executes the script while printing each command before it runs. bash -x script.sh This prints expanded commands to stderr, showing variable substitution and command execution order. You can enable tracing for specific…
Getting the running process PID in Bash Every shell script runs as a process with a unique ID (PID). You need this ID for process management, logging, temporary file naming, and cleanup operations. The $$ variable The special variable $$ expands to the PID of the current shell process: echo $$ This returns a single…
Finding the disk where root is mounted On Linux systems, the root filesystem (/) can be on various device types — a raw disk partition, an LVM logical volume, or other storage configurations. Finding the underlying physical disk requires checking the device hierarchy, which differs depending on the storage setup. Quick method with df and…
Getting the Next Character in ASCII Table with Bash Sometimes you need to find the ASCII character that comes after a given character. This is useful for generating sequences, creating substitution ciphers, or manipulating character ranges in shell scripts. Using printf with ASCII Values The most portable and straightforward approach uses printf to convert between…
Checking Your Zimbra Version The most direct way to check your Zimbra installation version is through the zmcontrol utility: zmcontrol -v This returns the version string of your Zimbra deployment. Run this command on any Zimbra server in your environment — the output will be identical across all nodes in a cluster. Alternative Methods If…
Extracting and Removing Trailing Numbers from Strings Extracting or removing trailing numbers from strings is a common task in shell scripting. Whether you’re parsing log files, processing configuration values, or cleaning up filenames, you’ll need reliable methods to handle these operations. Using Parameter Expansion The cleanest approach uses bash parameter expansion, which doesn’t require external…
Converting Epoch Timestamps to Readable Dates Bash provides straightforward methods to convert Unix epoch timestamps into human-readable formats. This is essential for log parsing, system monitoring, and scripting across CI/CD pipelines and production environments. Using the date Command The standard approach is the date command with the -d flag (GNU coreutils) or -r flag (BSD/macOS):…
Getting Hostname in Bash in Linux Retrieving the hostname of the machine running your script is essential for logging, node identification in distributed systems, monitoring, and conditional logic based on where code executes. Bash offers multiple approaches with different tradeoffs. Using the $HOSTNAME Variable The quickest method is the $HOSTNAME environment variable, which Bash sets…
Getting Environment Variables in Java There are two primary ways to access environment variables in Java: System.getenv() for reading variables and System.getProperty() for reading system properties. They’re different things, so understanding which one you need matters. Reading Environment Variables with System.getenv() System.getenv() retrieves variables set in your shell or container environment: String javaHome = System.getenv(“JAVA_HOME”);…
Getting Epoch Timestamps in Bash The date command is your primary tool for retrieving Unix epoch timestamps. It’s available on virtually all Unix-like systems and integrates seamlessly into scripts and command pipelines. Basic Epoch Timestamp date +%s This returns the number of seconds since January 1, 1970 UTC. Output looks like 1735689600. Higher Precision with…
Environment variables store configuration settings for your shell and applications. They’re essential for configuring containers, serverless functions, application runtime behavior, and system services. Retrieving an environment variable Use the dollar sign prefix to access a variable: echo $VARIABLE_NAME This prints the variable’s value to stdout. If the variable doesn’t exist, it prints an empty line….
Multithreaded Sorting in Linux The standard sort command is single-threaded by default, which limits performance on modern multi-core systems. Several approaches exist to speed up sorting operations using parallelism. GNU Sort with Parallel Sorting Modern versions of GNU sort (8.23+) include built-in parallel sorting support. Enable it with the –parallel flag: sort –parallel=4 large_file.txt >…