How to Get the Process ID (PID) in Python The PID is useful for logging, creating lock files, and process management. The Code import os print(os.getpid()) Python in 2026 In 2026, Python 3.12+ is the standard. While os.getpid() is the classic way, the multiprocessing module is often used in high-concurrency apps to manage child processes….
How to disable the DHCP service in dnsmasq on Linux? That is, to leave only dnsmasq’s DNS service. The `/etc/dnsmasq.conf` file may have lines that enable DHCP service of dnsmasq. By default, the DHCP is disabled in dnsmasq (check one example dnsmasq.conf file). To disable DHCP service in dnsmasq, in `/etc/dnsmasq.conf`, remove or disable the…
How to split a string by string in PHP? For example, “a string separated by space” => [“a”, “string”, “separated”, “by”, “space”] and “a,string,separated,by,comma” => [“a”, “string”, “separated”, “by”, “comma”] The commonly used `explode()` is not enough here because multiple delimiters should be consider as one (such as ” “, 3 spaces together, is consider…
In C, what’s the standard or common data structure for a list of objects? In C, one common way to store a list/collection of objects of the same type is to use one-dimensional arrays. In C, an array is a collection of data objects of the same type. An array is in a contiguous memory…
In C++, what’s the standard or common data structure for a list of objects? In C++, the common data structure for a sequence (“list”) of objects may be std::vector. A vector is a dynamically resizable array. It is “The most extensively used container in the C++ Standard Library …, offering a combination of dynamic memory…
Could you list the most important features or aspects for the C++ programming languages that describe its most important features/domains that are different from the others? For C++, as in Going Native 2012 Keynote by Bjarne Stroustrup: light-weight abstraction Key strengths: infrastructure software resource-constrained applications
How to Get the Hostname in C The gethostname function is the standard POSIX way to retrieve the system’s name. The Code #include <unistd.h> char hostname[1024]; gethostname(hostname, sizeof(hostname)); C in 2026 In 2026, while gethostname is still standard, modern C applications running in containers (Docker/Kubernetes) often retrieve their identity from environment variables (like HOSTNAME or…
How to Get the Hostname in Go Go provides a simple function in the os package to get the system’s hostname. The Code import “os” hostname, err := os.Hostname() Go in 2026 In 2026, Go 1.26+ is the standard. In cloud-native development, os.Hostname() usually returns the Pod name in Kubernetes or the Container ID in…
In C++, how to get the hostname of the node? In C++, the C way works too. However, with Boost, you can use the boost::asio::ip::host_name() function to get the hostname as a std::string: namespace boost { namespace asio { namespace ip { /// Get the current host name. BOOST_ASIO_DECL std::string host_name(); … More at http://www.boost.org/doc/libs/1_63_0/boost/asio/ip/host_name.hpp…
In Bash, how to convert an epoch timestamp to a human readable date format? In Bash, you can use the date command’s -d option: date -d @<your epoch> Here @ specifies the epoch timestamp. One example: $ date -d @1490157520.05 Wed Mar 22 12:38:40 HKT 2017
In Python, how to get the hostname of the node? In Python, you can get the hostname by the socket.gethostname() library function in the socket module: import socket hostname = socket.gethostname() Example: $ python Python 2.7.5 (default, Nov 6 2016, 00:28:07) [GCC 4.8.5 20150623 (Red Hat 4.8.5-11)] on linux2 Type “help”, “copyright”, “credits” or “license”…
How to Get the Epoch Timestamp in C The epoch timestamp (seconds since Jan 1, 1970) is the standard for timekeeping in Unix systems. The Code #include <time.h> time_t now = time(NULL); C in 2026 In 2026, time(NULL) remains the standard for second-level precision. For higher precision, clock_gettime(CLOCK_REALTIME, &ts) provides nanosecond accuracy. In modern systems,…
How to convert an epoch timestamp to a human readable date format? In Python: import time time.strftime(“%a, %d %b %Y %H:%M:%S %Z”, time.localtime(epoch)) One example: $ python Python 2.7.5 (default, Nov 6 2016, 00:28:07) [GCC 4.8.5 20150623 (Red Hat 4.8.5-11)] on linux2 Type “help”, “copyright”, “credits” or “license” for more information. >>> import time >>>…
How to Get the Epoch Timestamp in Java Java provides several ways to get the current time in milliseconds or seconds. The Code long epochMillis = System.currentTimeMillis(); long epochSeconds = Instant.now().getEpochSecond(); Java in 2026 In 2026, Java 21+ is the standard. The modern java.time package (introduced in Java 8) is preferred over the legacy Date…
In PHP, how to get the epoch timestamp, the number of seconds passed since the epoch? In PHP, you can use the time() function. ts = time(); To get the microsecond together too as a float number, use the microtime(true) function. ts2 = microtime(true); Example: $ php -a Interactive shell php > echo time() ….
How to Get the Epoch Timestamp in Perl The Unix epoch (seconds since Jan 1, 1970) is a standard way to represent time in computing. The Code my $epoch = time(); Perl in 2026 While Perl is less common for new web projects in 2026, it remains a powerhouse for system administration and text processing….
How to Get the Epoch Timestamp in Python Python’s time and datetime modules provide flexible time handling. The Code import time epoch_seconds = int(time.time()) Python in 2026 In 2026, Python 3.12+ is the standard. While time.time() is the classic choice, the datetime module is often preferred for its readability: int(datetime.now(timezone.utc).timestamp()). For high-precision logging, time.time_ns() provides…
In Java, how to get the value (string) of an environment variable? You may call the System.getenv(name) library function in Java to get the environment variable value. public static String getenv(String name) Parameters: name – the name of the environment variable Returns: the string value of the variable, or null if the variable is not…
How to Get the Epoch Timestamp in Bash The date command is the standard tool for time manipulation in the shell. The Command date +%s Bash in 2026 In 2026, Bash 5.2+ is the standard. For higher precision, you can use date +%s%N to get nanoseconds. In scripting, epoch timestamps are essential for creating unique…
In Python, how to get the value (string) of an environment variable? In Python, all environment variables can be accessed directly through os.environ import os print os.environ[‘HOME’] If the environment variable is not present, it will raise a KeyError. You can use get to return None if the environment variable is not present: print os.environ.get(‘ENV_MIGHT_EXIST’)…