What is better?
My general rule of thumb is that bash is fine when the equivalent Python would mostly be a whole bunch of `subprocess.run` commands. But as soon as you're trying to do a bunch of logic and you're reaching for functions and conditionals and cases... just break out Python.
call([options.cmake_path,'-G','Visual Studio 16','-A','x64','-S','.','-B',build_folder],check=True)
import os
os.rename(“src.txt”, “dest.txt”)
?Now, show us `mycommand | sed 's/ugly/beautiful/g' | awk -F: '{print $2,$4}' 1> something.report 2> err.log` in Python.
Like.
myvar = `mycommand | sed 's/ugly/beautiful/g' | awk -F: '{print $2,$4}' 1> something.report 2> err.log`
But if all I need to do is generate the report I proposed...why would I embed that in a Ruby script (or a Python script, or a Perl script, etc.) when I could just use a bash script?
os.system('mycommand | sed 's/ugly/beautiful/g' | awk -F: '{print $2,$4}' 1> something.report 2> err.log')
If it became unwieldy you’d turn it into a script:
#!/bin/sh
beautify() {
sed -e ‘
s/ugly/beautiful/g
…other stuff
‘
}
select() {
awk ‘
{print $2, $4}
…other stuff
‘
}
mycommand | beautify | select
For me, the "line in the sand" is not so much whether something is "safer" in a different language. I often find this to be a bit of a straw-man that stands in for skill issues - though I won't argue that shell does have a deceptively higher barrier to entry. For me, it is whether or not I find myself wanting to write a more robust test suite, since that might be easier to accomplish with Ginkgo or pytest or `#include <yourFavorateTestLibrary.h>`.
If your position is that we should not be writing bash but instead Python, then yes, it is absolutely fair.
> the benefit of which is that I can actually read it.
And you couldn't read the command pipeline I put together?
> What happens if you want to retry a line if it fails?
Put the thing you want to do in a function, execute it on a line, if the sub-shell returns a failure status, execute it again. It isn't like bash does not have if-statements or while-loops.
> And you couldn't read the command pipeline I put together?
It took me multiple goes, but the equivalent in python I can understand in one go.
> Put the thing you want to do in a function, execute it on a line, if the sub-shell returns a failure status, execute it again. It isn't like bash does not have if-statements or while-loops.
But when you do that, it all of a sudden looks a lot more like the python code
from subprocess import Popen, PIPE
CMD = ("printf", "x:hello:67:ugly!\nyy$:bye:5:ugly.\n")
OUT = "something.report"
ERR = "err.log"
def beautify(str_bytes):
return str_bytes.decode().replace("ugly", "beautiful")
def filter(str, \*index):
parts = str.split(":")
return " ".join([parts[i-1] for i in index])
with open(OUT, "w") as out, open(ERR, "w") as err:
proc = Popen(CMD, stdout=PIPE, stderr=err)
for line_bytes in proc.stdout:
out.write(filter(beautify(line_bytes), 2, 4))
Edit: this is proving very difficult to format on mobile, sorry if it's not perfect.
I also think bun alongside typescript is quite viable, especially with the shell interop:
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