SysTutorials Posts

Web Development

Configuring Zimbra Web Service Hostname and Port
ByEric Ma Mar 24, 2018Apr 13, 2026

Zimbra’s web interface needs proper hostname and port configuration to function correctly, especially when you’re deploying behind load balancers, reverse proxies, or in clustered environments. Viewing Current Configuration Check your current Zimbra web service hostname and port settings: zmprov getServer $(zmhostname) zimbraMailPort zmprov getServer $(zmhostname) zimbraMailSSLPort zmprov getServer $(zmhostname) zimbraAdminPort You can also query the…

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Linux & Systems Administration

Getting the Next ASCII Character in Bash
ByDavid Yang Mar 24, 2018Apr 11, 2026

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 characters and their ASCII numeric values: #!/bin/bash get_next_char() {…

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Linux & Systems Administration

Disabling DHCP in dnsmasq on Linux
ByQ A Mar 24, 2018Apr 13, 2026

If you’re running dnsmasq primarily for DNS resolution and don’t need its DHCP server capabilities, you’ll want to disable DHCP while keeping DNS functional. This is a common configuration for DNS-only setups or when another service handles DHCP. Default dnsmasq behavior By default, dnsmasq ships with DHCP disabled. However, many distributions include preconfigured DHCP settings…

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Languages & Frameworks

How to Split Strings in PHP
ByQ A Mar 24, 2018Apr 13, 2026

The basic explode() function works when you have a single delimiter character, but fails when multiple consecutive delimiters should be treated as one. For example: “a string separated by space” (three spaces) should split into [“a”, “string”, “separated”, “by”, “space”] “a,,string,,separated” (double commas) should split into [“a”, “string”, “separated”] Use preg_split() with regex patterns to…

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Linux & Systems Administration

Extracting or Removing Trailing Numbers in Bash
ByDavid Yang Mar 24, 2018Apr 13, 2026

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 commands and works in all POSIX-compliant shells….

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Linux & Systems Administration

How to Split a String by Delimiter in Bash
ByEric Ma Mar 24, 2018Apr 13, 2026

Bash doesn’t have a built-in split function, but you can achieve string splitting through several methods. The most common approach uses IFS (Internal Field Separator), though other techniques exist depending on your needs. IFS with read The simplest method for splitting a string by a delimiter: string=”apple,banana,cherry” IFS=’,’ read -ra ADDR <<< “$string” for i…

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Design Patterns & Architecture

Common Data Structures for Object Lists in C
ByQ A Mar 24, 2018Apr 13, 2026

In C, the most straightforward way to store a homogeneous collection of objects is an array. An array is a contiguous block of memory holding elements of identical type, with the first element at the lowest address and subsequent elements following immediately after. Arrays provide O(1) random access to any element and are efficient for…

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Languages & Frameworks

Standard Data Structures for Object Lists in C++
ByQ A Mar 24, 2018Apr 13, 2026

In C++, std::vector is the standard go-to container for managing sequences of objects. It’s a dynamically resizable array that combines efficient random access with automatic memory management. A vector stores elements contiguously in memory, supporting: O(1) random access via indexing O(1) amortized push/pop operations at the end O(n) insertions and deletions in the middle Automatic…

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Languages & Frameworks

Key Features of C++ Every Developer Should Know
ByQ A Mar 24, 2018Apr 12, 2026

C++ remains a foundational language for systems programming and performance-critical applications. Here’s what actually matters when choosing C++ for a project. Zero-Cost Abstraction This is C++’s defining characteristic. You get high-level language features—classes, templates, standard library containers—without paying runtime overhead. The compiler eliminates abstraction layers during compilation. This means you can write clean, maintainable code…

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Languages & Frameworks

Getting the Hostname in Go
ByQ A Mar 24, 2018Apr 13, 2026

Go’s os package provides a straightforward function to retrieve the system’s hostname: package main import ( “fmt” “os” ) func main() { hostname, err := os.Hostname() if err != nil { fmt.Println(“Error:”, err) return } fmt.Println(“Hostname:”, hostname) } The os.Hostname() function returns a string containing the hostname and an error value. Always check the error—it…

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Languages & Frameworks

Retrieving the Node’s Hostname in C++
ByQ A Mar 24, 2018Apr 13, 2026

Retrieving the hostname of the current system is a common task in systems programming, network applications, and monitoring tools. C++ provides several approaches depending on your platform and requirements. Using gethostname() The most portable approach uses the gethostname() function from <unistd.h>: #include <unistd.h> #include <iostream> #include <cstring> int main() { char hostname[256]; if (gethostname(hostname, sizeof(hostname))…

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Linux & Systems Administration

Retrieving Hostname in C Programs on Linux
ByQ A Mar 24, 2018Apr 13, 2026

The gethostname() function is the standard POSIX way to retrieve the system’s hostname. It’s straightforward to use and works across Unix-like systems. Basic Implementation #include <unistd.h> #include <stdio.h> int main() { char hostname[256]; if (gethostname(hostname, sizeof(hostname)) == 0) { printf(“Hostname: %s\n”, hostname); } else { perror(“gethostname”); return 1; } return 0; } The function takes…

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Languages & Frameworks

Getting a Node’s Hostname in Python
ByQ A Mar 24, 2018Apr 13, 2026

There are several ways to retrieve the hostname of the current machine in Python, each with different use cases. Using socket.gethostname() The simplest and most common approach is the socket module, which is part of Python’s standard library: import socket hostname = socket.gethostname() print(hostname) This returns the hostname as a string. On most systems, this…

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Linux & Systems Administration

Getting the Hostname in Bash: 3 Methods
ByEric Ma Mar 24, 2018Apr 13, 2026

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 at shell initialization: echo $HOSTNAME host01…

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Linux & Systems Administration

Converting Epoch Timestamps to Readable Dates in Bash
ByQ A Mar 24, 2018Apr 13, 2026

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): Linux (GNU date) date -d @1234567890…

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Languages & Frameworks

Converting Epoch Timestamps to Readable Dates in Python
ByQ A Mar 24, 2018Apr 13, 2026

Epoch timestamps (seconds since January 1, 1970 UTC) are common in logs, databases, and APIs. Python’s datetime module handles conversion cleanly. Basic Conversion The simplest approach uses datetime.fromtimestamp(): from datetime import datetime epoch = 1609459200 dt = datetime.fromtimestamp(epoch) print(dt) # 2021-01-01 00:00:00 For UTC times specifically, use utcfromtimestamp(): from datetime import datetime, timezone epoch =…

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Programming Languages

Converting Unix Timestamps in C
ByQ A Mar 24, 2018Apr 13, 2026

The epoch timestamp (seconds since January 1, 1970 UTC) is fundamental for Unix timekeeping. Every process needs reliable time access — whether for logging, scheduling, or benchmarking. Basic Second-Level Precision For simple timestamp needs, use time(): #include <time.h> time_t now = time(NULL); printf(“Current epoch: %ld\n”, (long)now); This returns seconds since epoch as a time_t. It’s…

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Languages & Frameworks

Getting the Current Epoch Timestamp in Java
ByQ A Mar 24, 2018Apr 13, 2026

Java provides multiple ways to get the current time as an epoch value. The right approach depends on whether you need milliseconds, seconds, or nanosecond precision, and whether you’re working with UTC or time zones. Using Instant for UTC timestamps The most straightforward method is Instant.now(): Instant now = Instant.now(); long epochSeconds = now.getEpochSecond(); long…

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Programming Languages

Getting Epoch Timestamps in Perl
ByQ A Mar 24, 2018Apr 13, 2026

The Unix epoch (seconds since January 1, 1970 UTC) is the standard for representing time across systems. Perl gives you straightforward access to this value. Basic epoch timestamp The simplest way to get the current epoch time: my $epoch = time(); print $epoch; # prints something like 1735689600 The time() function returns an integer representing…

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Languages & Frameworks

Getting Epoch Timestamps in PHP
ByQ A Mar 24, 2018Apr 13, 2026

The epoch timestamp (also called Unix time) represents the number of seconds since January 1, 1970, 00:00:00 UTC. PHP provides several straightforward methods to obtain this value. Using time() The simplest approach is the time() function: <?php $timestamp = time(); echo $timestamp; // Output: 1704067200 (example) ?> This returns the current Unix timestamp as an…

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