Regular expressions originated in 1951, when mathematician Stephen Cole Kleene described regular languages using his mathematical notation called regular events. History Stephen Cole Kleene, who introduced the concept Regular expressions are supported in many programming languages. Regular expressions are used in search engines, in search and replace dialogs of word processors and text editors, in text processing utilities such as sed and AWK, and in lexical analysis. Different syntaxes for writing regular expressions have existed since the 1980s, one being the POSIX standard and another, widely used, being the Perl syntax. They came into common use with Unix text-processing utilities. The concept of regular expressions began in the 1950s, when the American mathematician Stephen Cole Kleene formalized the concept of a regular language. Regular expression techniques are developed in theoretical computer science and formal language theory. Usually such patterns are used by string-searching algorithms for "find" or "find and replace" operations on strings, or for input validation. The main contributors of the BashGuide, BashFAQ, BashPitfalls and ShellCheck hang around there.Blue highlights show the match results of the regular expression pattern: /h+/ g (the letter h followed by one or more vowels)Ī regular expression (shortened as regex or regexp sometimes referred to as rational expression ) is a sequence of characters that specifies a match pattern in text. (Archived) The Bash-Hackers Wiki – Extensive resource. ShellCheck – Automatically detects problems with shell scripts.īashFAQ – Answers most of your questions.īashPitfalls – Lists the common pitfalls beginners fall into, and how to avoid them. Google's Shell Style Guide – Reasonable advice about code style.Įxplainshell - Explain complex shell operations. Update : Course is currently being rewritten Other Shells: /r/zsh, /r/fishshell, /r/oilshell, /r/batchīeginner's Guide to Command Line – A crash course for some common unix and shell commands. /r/devops – for discussion and support around DevOps technologies./r/sysadmin – for content and discussion for system administrators./r/linuxadmin – for content and support around Linux system administration./r/linuxquestions – for more general Linux questions./r/commandline, /r/shell – for anything regarding the command line, in any operating system.If you don’t flair your post, the moderators will set the most appropriate flair. Critique – You are submitting a creation of your own (usually a Bash script) and actively seek feedback on it and how to improve it.Submission – General submission of any kind (link or text post).Solved – The submission used to be flaired as “help”, but your problem has been solved, or your question has been answered.“help” posts are usually self posts, though you may also submit a link to a thread in a different subreddit (e. Help – You seek help, or want to ask a question.You can choose one of these four flairs for your post: Links from the sidebar count as having been submitted already, so posting them without new context is also considered a repost. because you’d like to discuss another part of it, or because something has changed since the last time it was submitted, or because the link was updated since then). This is meant with regards to content, not just “the same link was submitted earlier” – it’s okay to resubmit an old link in some new context (e. However, the post should not be specific to another shell. This rule is interpreted generously general shell scripting content is mostly accepted.
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