On 4/16/22 09:47, Nicholas Geovanis wrote:
On 4/15/22 19:37, wilson wrote:Helloin shell script, how can I use regex to extract values from a string? maybe value types transformation should be required.for instance the string: "black berry 12". I want go get the name: black berry [String] the price: 12 [Int]I did this in other language such as java/scala:scala> val regex = """(.+)\s+(\d+)""".r val regex: scala.util.matching.Regex = (.+)\s+(\d+)scala> str match { | case regex(name,price) => (name,price.toInt) | } val res2: (String, Int) = (black berry,12)But sometimes for a simple task I won't want to write a java program. so what's the shell solution?
When I first read the above, my thought was "Any language can parse lines of input. What are you going to do with $name and $price once you have them?" E.g. think about your input data, your data structures, your algorithms, and your output requirements when picking a programming/ scripting language.
That said, platform capabilities are also important. A script written to use /bin/sh and "standard system utilities" on Debian can be run on any Debian machine without needing to install any packages. But, the same script could very well fail on BSD because GNU userland tools look like Unix userland tools, but they are not. Caveat programmer.
I didn't want to spoil the party and say this. But now my hand is forced :-) You Mr Original Poster may find perl to be more congenial for regular expression use especially.
+1
You should find it on every single platform you find bash. Regardless of OS.
I use Bash for an interactive shell because I like its usability features. I use /bin/sh for scripts because of its portability (ignoring GNU vs. BSD userland issues). When I need more power, I use Perl.
But, Perl is no longer as ubiquitous as it used to be. Perl is not installed by default FreeBSD or Cygwin, for example. Python now seems to be the favored super shell scripting language. I have avoided Python because its syntax is whitespace dependent, but someone picking a "P" language to learn today should seriously consider Python.
David