PowerShell is open sourced and is available on Linux • Hacker News Board

Re: PowerShell is open sourced and is available on Linux

#91

Post by nitrogen » Thu, Aug 18, 2016, 4:08 PM UTC

soperj wrote: post #24

larrik wrote: post #17

Earlier quoted context omitted.

As a full-time Linux user, I have to say that bash is overrated. For instance, on Windows I could press the up arrow through my history 20x to find a group of commands I want to run, press Enter, then press DOWN for the following command, then enter, then DOWN until I run them all. In Bash, I need to press UP 20x every single time. Yes, you can customize it a lot, and you can script it but default bash isn't that spe…

Or just be sane and use ctrl-r and search.

I also highly recommend enabling the pgdn/pgup bindings for history-search-forward/backward. If you are searching for a prefix it's a bit easier than ^R.

Re: PowerShell is open sourced and is available on Linux

#92

Post by vvanders » Thu, Aug 18, 2016, 4:08 PM UTC

UK-AL wrote: post #81

vvanders wrote: post #50

Earlier quoted context omitted.

Yes, this is so awesome. Can't remember the exact parameter/field? Just dump it to the console.

That what you would do with text? If you have no idea what its outputting, explore it by putting it to the console.

Sure, but with text you might have empty fields that are just omitted. With Powershell you can see that the field exists but is empty.

There's a bunch of subtle distinctions like that which don't sound impressive but end up being really nice when working with it.

Re: PowerShell is open sourced and is available on Linux

#93

Post by dleslie » Thu, Aug 18, 2016, 4:09 PM UTC

Analemma_ wrote: post #6

PowerShell is my guilty pleasure of the computing world. Once you've piped strongly-typed objects around between your shell commands, text scraping seems barbaric by comparison. The problem, of course, is that you can't use all that power for much, since the pool of PS-compatible tools and utilities is much shallower than it is for Unix shells. I'm really hoping this will help spur a new wave of PowerShell-compatible…

As a note, there have been strongly-typed shell languages for Unix for some time. Scheme Shell[0], Turtle[1] and TCSH[2] leap to mind; but there's nothing preventing a developer from using Perl, Python, Lisp or any other language that allows itself to accept stdin as an interpreted script.

0: https://scsh.net/

1: http://www.haskellforall.com/2015/01/use-haskell-for-shell-s...

2: http://www.tcsh.org/Welcome

Edit: oh my, I posted the wrong link for tcsh. No one noticed, but my apologies nonetheless.

Re: PowerShell is open sourced and is available on Linux

#94

Post by ldiracdelta » Thu, Aug 18, 2016, 4:09 PM UTC

larrik wrote: post #17

tombert wrote: post #9

I'm always in favor of things being open-sourced, but I do kind of wonder in what universe I would use PowerShell when Bash is readily available.

As a full-time Linux user, I have to say that bash is overrated. For instance, on Windows I could press the up arrow through my history 20x to find a group of commands I want to run, press Enter, then press DOWN for the following command, then enter, then DOWN until I run them all. In Bash, I need to press UP 20x every single time. Yes, you can customize it a lot, and you can script it but default bash isn't that spe…

If you put this in your `~/.inputrc` [1]:

    "\e[A": history-search-backward
    "\e[B": history-search-forward
    "\e[C": forward-char
    "\e[D": backward-char

you can start typing a previous command and go up through your history for all commands starting with whatever you currently have typed into the bash shell. Reset the scrolling through the history with `ctrl+c`.

Personally, I hate that powershell remembers your position in the shell history. I don't want to maintain a mental model of the shell history rollodex and where I am in it. That's one less part of my brain that I can't use for thinking about the code. If I have a set of commands to type over and over:

    history 20 | head -10 | sed -r 's/^ *[0-9]+ *//g;' > new_script.bash

* [1] http://codeinthehole.com/writing/the-most-important-command-...

Re: PowerShell is open sourced and is available on Linux

#95

Post by mikestew » Thu, Aug 18, 2016, 4:09 PM UTC

petepete wrote: post #67

pm215 wrote: post #56

Earlier quoted context omitted.

You can use control-O for that, which does "execute this command as if I pressed enter, then when it's done bring up the following command in command line prompt". So if you have a set of commands to run that are 20 lines up in history, you can first find them (with 20x UP or by reverse-search), then just control-O control-O control-O control-O ... to execute them one after another.

I wasn't aware of this. Thank you. Not that I've been using Bash and zsh every day for twelve plus years...

Twelve? Youngster. I'd guess I'm coming up on thirty years. And I did not know this.

Now the trick is to remember it next time the need comes up. :-)

Re: PowerShell is open sourced and is available on Linux

#96

Post by jamespo » Thu, Aug 18, 2016, 4:09 PM UTC

satysin wrote: post #63

SixSigma wrote: post #27

Earlier quoted context omitted.

Bash is awful. But so are shells in general. Even Rob Pike says as soon as your shell program gets longer than a few lines, write it in a proper language.

I feel that principle is true from all high-level languages as you move down the chain. Shell scripts should be 1-20 lines. Python/Ruby/whatever for 20-100 and compiled for anything >100.

What if you use Nuitka or PyPy for Python, does that magically allow you across the arbitrary border?

Re: PowerShell is open sourced and is available on Linux

#97

Post by CodexArcanum » Thu, Aug 18, 2016, 4:10 PM UTC

tombert wrote: post #9

I'm always in favor of things being open-sourced, but I do kind of wonder in what universe I would use PowerShell when Bash is readily available.

Powershell is really more about the scripting language and the command processing. The "shell" part is modular. On Windows you can still use most cmd tools inside powershell and with its commands.

So you shouldn't give up bash, you should use both and take advantage of the tools that help you get the most done.

Re: PowerShell is open sourced and is available on Linux

#98

Post by oblio » Thu, Aug 18, 2016, 4:10 PM UTC

shadowmint wrote: post #34

Is this actually useful? I always thought powershell was largely just for interacting with windows components, like installing an msi or talking to active directory. What would you actually practically use this for on a linux box?

The ramp-up period is much lower with Powershell.

It is truly an interactive ("online") environment. Almost everything is typed and through introspection the shell can offer very rich auto-completion hints, without needing tedious scripts such as those used by bash/zsh.

Quick example:

get- cycles through all get-[whatever] commands, as you'd expect. get-certificate cycles through all parameters available for get-certificate get-certificate -ErrorAction cycles through the list of valid values for ErrorAction (there's like 6 of them: stop, suspend, etc.)

It is also highly standardized, there's a set of "verbs" allowed so that it's much easier to find something since everything is in a certain category (https://msdn.microsoft.com/en-us/library/ms714428(v=vs.85).a...)

It has its bad/ugly bits, but the principles are quite solid. In many ways they are what I'd expect if Richie and Thompson would have designed Unix in a modern environment (i.e. not an environment where the output of your commands would be printed :) ).

Re: PowerShell is open sourced and is available on Linux

#99

Post by philsnow » Thu, Aug 18, 2016, 4:10 PM UTC

aidos wrote: post #87

Cool! I'm having a play with it and it seems to work really nicely. Does anyone know why the following commands don't produce the same output? get-childitem | ConvertTo-Csv get-childitem | ConvertTo-Json | ConvertFrom-Json | ConvertTo-Csv It seems like, if there's a perfect underlying data model doing what's effectively an identity conversion shouldn't change anything. Edit oooo, and all the linux stuff is available…

I don't have a powershell handy, but one thing that might be causing changes is that json dictionaries usually don't have a defined order (parsing libraries are free to render the keys of a dictionary in any order); are the changes you're seeing just ordering changes?

Re: PowerShell is open sourced and is available on Linux

#100

Post by dsp1234 » Thu, Aug 18, 2016, 4:10 PM UTC

UK-AL wrote: post #39

amenod wrote: post #32

Earlier quoted context omitted.

Is this really so useful in practice? I have never used PowerShell before (nor do I have plans to do so in the near future), but I would imagine the downside is complexity, both for user and especially for developers. With text you just read and parse, while with objects you need to know the object type, its fields,... Whatever happend, I hope text stays here (and I have a bad feeling about it ever since I met system…

Objects are discoverable in powershell. Enter the object, and lists the object out as text.

More specifically, you can find out all of the type information about anything you get access to by piping it to 'get-member'

  get-netadapter | get-member

Which gives the following output http://pastebin.com/bM0cBeXb about the type information for the result of 'get-netadapter'. In addition to this, tab completion for properties is available.

Alternately, you can get all of the current properties of any existing object by piping to 'select' (to get a general subset) or 'select * ' to get all properties. Note that this gives all information for the objects in the pipeline.

  get-netadapter | select
  get-netadapter | select *

The first will provide a short list of fields for all network adapters, and the second will provide all properties.

'Select' can also be used to easily filter the properties of items in the pipeline to ones you care about.

  get-netadapter | select Name, MacAddress

You can also just generally filter the pipeline based on generic filters (give me all of the network adapters that are currently not enabled, and have a driver provided by Mellanox).

And ultimately, if you want to use powershell to do the stuff that typed objects are good at, and then leverage command line tools to do the rest, you can if you like.

  get-netadapter | select Name, MacAddress | exportto-csv

Which will take all of the network adapters, gather their name and mac address, and spit it out to stdout as CSV which can then be sent to any number of external tools, or using the '-expandproperty' flag to 'select' can give just a bare list of properties one on each line.