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What is bash extended globbing?
The program never sees the wildcards, bash substitutes the expansion into the command line before running the program. …
What is an extended glob?
Extended globs gives us more of the power of regular expressions for globbing. Unlike character sets or character classes, patterns can be more than one character and we can match multiple occurrences of a pattern.
How do I match a pattern on glob extended?
Bash Pattern matching and regular expressions Extended globbing
- ?(pattern-list) – Matches zero or one occurrence of the given patterns.
- *(pattern-list) – Matches zero or more occurrences of the given patterns.
- +(pattern-list) – Matches one or more occurrences of the given patterns.
What is a Bash glob?
Globs. “Glob” is the common name for a set of Bash features that match or expand specific types of patterns. Some synonyms for globbing (depending on the context in which it appears) are pattern matching, pattern expansion, filename expansion, and so on. A glob may look like *.
Is there a way to extend a Glob in Bash?
Bash’s built-in extglob option can extend a glob’s matching capabilities The following sub-patterns comprise valid extended globs: The pattern-list is a list of globs separated by |. The pattern-list itself can be another, nested extended glob.
Which is the best syntax for Extended Globbing?
However, probably the most interesting extended globbing syntax is the “! (…)” syntax for matching everything except (ie not matching). But, be careful, this doesn’t always do what you might expect. For example, let’s list all the files that aren’t JPEGs or GIFs. One’s first thought might be something like this:
Why does Bash not expand when calling exec ( )?
The program never sees the wildcards, bash substitutes the expansion into the command line before running the program. This is rarely important except when you’re writing code and calling exec () and friends: if you don’t execute the program via bash any wildcards in the command line that you pass to exec () won’t get expanded.
How is the pathname expansion done in Bash?
A subtle point about pathname expansion that is not often understood is that it is done by bash and not by the operating system or by the program that is being run. The program never sees the wildcards, bash substitutes the expansion into the command line before running the program.