[Discussion] POSIX, the Love of Backticks and All That Jazz


 
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# 15  
Old 01-28-2017
Yes - although I am sure the move to the "expert users" helped as well.

As to why would anyone (still use) backticks:
a) I am not an expert scripter
b) I have used backticks over 38 years - as well as () (not $())
c) I make typo mistakes when using () - oops, that needs to be $()

In short - I write simple scripts - really simple ones - not save the world ones, and backticks work fine for me.

However, as I said before - I hope this dog is not too old - and I shall start to remember the $ in front of the ()
# 16  
Old 01-30-2017
Lets not get deep into subshells.

I'm sure you experts don't have too many nested subshells in your code Smilie
In my opinion, it lowers the control you have in your program.

So if you have small, efficient script with no nested subshells, are backquotes still the lowest denominator e.g will it run without magic cookie on any unix OS ever produced ?

Example would be a simple mv script using basename command in subshell.
# 17  
Old 01-30-2017
Any system you will encounter nowadays will most likely contain a POSIX compliant shell. So I would code for that and I really do not see a need for backticks anymore.

There hardly is a reason nowadays why a new script would need to be able to run in a Bourne shell, which would require the backticks..
# 18  
Old 01-30-2017
Quote:
Originally Posted by Peasant
So if you have small, efficient script with no nested subshells, are backquotes still the lowest denominator e.g will it run without magic cookie on any unix OS ever produced ?
I would never run the risk of having whatever shell executing my code. Out of pure paranoia you won't see any script without a shebang line stating the shell it is intended to run in explicitly.

You see, i once wrote shell scripts for an installed base of ~22k systems worldwide, ranging from IBM 42Ts and 43Ps (desktop systems) up to big SP/2s and everything in between. Believe me, whatever administrative horror you are able to think of - 5 systems somewhere had exactly this and then some. root not allowed to write a file in /tmp? Filesystems with no more free inodes? A user named "root" but with a non-0 UID? I have seen all this and more.

Most of my scripts are not "small" therefore. Not, because they do so much, but because they take extreme care of error handling and take nothing i can think of for granted.

Quote:
Originally Posted by Peasant
Example would be a simple mv script using basename command in subshell.
basename is IMHO a bad example. I would do that with parameter expansion as (in the interest of speed) anything else that could be done with it.

bakunin
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