In many C++ IDE’s and compilers, when it generates the main function for you, it looks like this: int main(int argc, char *argv[]) When I code C++ without an IDE, just with a command line compiler, I type: int main() without any parameters. What does this mean, and is it vital to my program? 8 … Read more
What is a good way of parsing command line arguments in Java? 20 s 20 Check these out: http://commons.apache.org/cli/ http://www.martiansoftware.com/jsap/ Or roll your own: http://docs.oracle.com/javase/7/docs/api/java/util/Scanner.html For instance, this is how you use commons-cli to parse 2 string arguments: import org.apache.commons.cli.*; public class Main { public static void main(String[] args) throws Exception { Options options = … Read more
I am originally a C programmer. I have seen numerous tricks and “hacks” to read many different arguments. What are some of the ways Python programmers can do this? Related What’s the best way to grab/parse command line arguments passed to a Python script? Implementing a “[command] [action] [parameter]” style command-line interfaces? How can I … Read more
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I have several hundred PDFs under a directory in UNIX. The names of the PDFs are really long (approx. 60 chars). When I try to delete all PDFs together using the following command: rm -f *.pdf I get the following error: /bin/rm: cannot execute [Argument list too long] What is the solution to this error? … Read more
Can I pass variables to a GNU Makefile as command line arguments? In other words, I want to pass some arguments which will eventually become variables in the Makefile. 8 s 8 You have several options to set up variables from outside your makefile: From environment – each environment variable is transformed into a makefile … Read more
I would like to use argparse to parse boolean command-line arguments written as “–foo True” or “–foo False”. For example: my_program –my_boolean_flag False However, the following test code does not do what I would like: import argparse parser = argparse.ArgumentParser(description=”My parser”) parser.add_argument(“–my_bool”, type=bool) cmd_line = [“–my_bool”, “False”] parsed_args = parser.parse(cmd_line) Sadly, parsed_args.my_bool evaluates to True. … Read more
I would like my Bash script to print an error message if the required argument count is not met. I tried the following code: #!/bin/bash echo Script name: $0 echo $# arguments if [$# -ne 1]; then echo “illegal number of parameters” fi For some unknown reason I’ve got the following error: test: line 4: … Read more
I am writing a very simple script that calls another script, and I need to propagate the parameters from my current script to the script I am executing. For instance, my script name is foo.sh and calls bar.sh foo.sh: bar $1 $2 $3 $4 How can I do this without explicitly specifying each parameter? 12 … Read more
I have a rake task that needs to insert a value into multiple databases. I’d like to pass this value into the rake task from the command line, or from another rake task. How can I do this? 20 20 Options and dependencies need to be inside arrays: namespace :thing do desc “it does a … Read more
