The UNIX® Standard | www.opengroup.org
May 22, 2025 · Single UNIX Specification- “The Standard” The Single UNIX Specification is the standard in which the core interfaces of a UNIX OS are measured. The UNIX standard includes a rich feature …
What are the special dollar sign shell variables? - Stack Overflow
Sep 14, 2012 · In Bash, there appear to be several variables which hold special, consistently-meaning values. For instance, ./myprogram &; echo $! will return the PID of the process which …
unix - what does '$?' mean in a shell script? - Stack Overflow
Oct 5, 2012 · I came across a shell script that contains a statement like, if [ $val -eq $? ] What does $? mean here?
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What does the line "#!/bin/sh" mean in a UNIX shell script?
Sep 10, 2011 · When you try to execute a program in unix (one with the executable bit set), the operating system will look at the first few bytes of the file. These form the so-called "magic number", …
unix - Why is 1/1/1970 the "epoch time"? - Stack Overflow
Jun 23, 2011 · The definition of unix time and the epoch date went through a couple of changes before stabilizing on what it is now. But it does not say why exactly 1/1/1970 was chosen in the end.
scripting - What does $$ mean in the shell? - Stack Overflow
Sep 17, 2008 · Every process in a UNIX like operating system has a (temporarily) unique identifier, the PID. No two processes running at the same time can have the same PID, and $$ refers to the PID of …
Converting unix time into date-time via excel - Stack Overflow
Explanation Unix system represent a point in time as a number. Specifically the number of seconds* since a zero-time called the Unix epoch which is 1/1/1970 00:00 UTC/GMT. This number of seconds …
Difference between CR LF, LF and CR line break types
Oct 12, 2009 · I'd like to know the difference (with examples if possible) between CR LF (Windows), LF (Unix) and CR (Macintosh) line break types.
How can I convert bigint (UNIX timestamp) to datetime in SQL Server?
Adding n seconds to 1970-01-01 will give you a UTC date because n – the Unix timestamp – is the number of seconds that have elapsed since 00:00:00 Coordinated Universal Time (UTC), Thursday, …