[RESOLVED] How I pass in my command-line variables disgusts me

Question

Hello,
What I'm trying to do is to make an easily configurable script that the user can run with just a few basic command line variables (some of our users are not programmers.)  Now, here's my problem, when it comes to extracting the variables from the command line, it's kind of messy.  Lets say I have the following command:
$ ./hl_script.sh --config-file=config_abc.txt --rate=5000 --data-dump=/opt/dump_area -v
"-v" means verbose
Now, given the weird arrangement of the different types of command line arguments, I'd like to extract the salient parts of the information that I care about.  However, at this moment, all I have is the "cut" command which can easily get into undefined behavior territory should the user misstype an input.  I would love to know how you have done this and what your approach to this problem is.
This is the code that I have so far:
# this is where we run the initial test and check if the user entered the
# help flag in order to see how to properly use this application.
if [ $# -gt 1 ]; then
for argument in $@
do
if [ $argument = "--help" ]; then
echo "Here is how you would use this software and the flags that would"
echo " be useful."
echo " --help"
echo " Brings up this display and shows a listing of the options"
echo " that can be used to better utilize this app."
echo ""
echo " --config-file=N"
echo " Specify the config file that we'd like to use."
echo ""
exit 0
elif [ `cut $argument | cut -d'=' -f 1` = "--config-file" ]; then
# read-in the config file that we specified and then proceed to set a
# bunch of environment variables that we need.
echo "stuff..."
fi
done
fi
Last edited by publicus (2014-05-13 13:13:43)

Answer 1

ewaller wrote:
I know your sample code is Bash, but you may want to consider doing it in Python and using this library
Here is a simple Python program I wrote that uses the library:
ewaller$@$odin ~/devel/python 1004 %./sieve.py
Usage: sieve.py [options] arg
sieve.py: error: incorrect number of arguments
ewaller$@$odin ~/devel/python [2]1005 %./sieve.py 10
2 3 5 7
ewaller$@$odin ~/devel/python 1006 %./sieve.py --help
Usage: sieve.py [options] arg
Find prime numbers using a sieve of Eratosthenes
Options:
-h, --help show this help message and exit
-v, --verbose
ewaller$@$odin ~/devel/python 1007 %./sieve.py 10 -v
removing 4
removing 6
removing 8
removing 10
removing 6
removing 9
removing 10
2 3 5 7
ewaller$@$odin ~/devel/python 1008 %cat sieve.py
#! /usr/bin/python
Implement a sieve of Eratosthenes
from optparse import OptionParser
def main():
#Handle all the command line nonsense. We need a number as an argument
usage = "%prog [options] arg"
description = "Find prime numbers using a sieve of Eratosthenes"
parser = OptionParser(usage=usage,description=description)
parser.add_option("-v", "--verbose", action="store_true", dest="verbose")
(options, args) = parser.parse_args()
if len(args) != 1:
parser.error("incorrect number of arguments")
try:
maxval=eval(args[0])
except:
parser.error ("Argument is not a number")
# Here is the sieve
a=[x for x in range(0,maxval+1)]
for count in range(2,int(maxval/2)+1):
if a[count]:
for i in range(count*2,maxval+1,count):
a[i]=0
if options.verbose:
print ("removing %i"%i)
# and report the results
wrap=0
for count in range(2,len(a)):
if a[count]:
print (count,end=" ")
wrap += 1
if (wrap == 5):
print()
wrap = 0
print ()
if __name__ == "__main__":
main()
ewaller$@$odin ~/devel/python 1009 %
The thing is, I already have some shell code written that works, so I don't want to re-write (and re-test) that.