For questions relating to shells and kernels.

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26
votes
3answers
14k views

Difference between a REPL and interactive shell

Noob question. I am not quite able to tell the difference between a REPL and an interactive shell just by reading the definitions on Wikipedia. Wiki notes that REPL is a particular kind of ...
18
votes
12answers
8k views

Interviewing someone for general unix skills [closed]

How would you test a developer that claims to have *nix shell experience (just to be clear, we don't want to test if someone can develop on *nix, only that they know their way around the command ...
16
votes
9answers
2k views

What were the reasons why Windows never had a decent shell? [closed]

I was reading a topic on SO: Why are scripting languages (e.g. ...) not suitable as shell languages?. Especially I liked the answer by Jörg W Mittag, from which I learned interesting things about ...
13
votes
8answers
7k views

What's shell script's advantage over interpreted programming languages? [closed]

(I'm not sure if it's a appropriate question here) Shell scripts, like those written in bash, can do many things. They can call Unix programs, pipe their output, redirect I/O from/to files, control ...
10
votes
3answers
2k views

User Configuration of a Shell Script. Best practices?

I am writing a shell script with a few variables that should be configured by the user. There will be an installer for downloading and configuring the script, possibly by asking a series of question. ...
8
votes
4answers
2k views

why empty function are needed

I started learning python and I am wondering why empty function are needed in a programming language e.g. in python: def empty_func(): pass even in shell scripts empty function empty functions ...
6
votes
1answer
3k views

Is it possible to use python as a shell replacement? [duplicate]

Recently I was looking at python's shutil and subprocess etc... And I started wondering: wouldn't it be ok to use python instead of e.g. bash? What am I missing?
5
votes
2answers
4k views

Why most use Cygwin and not Uwin?

Most academic researchers I know target just *nix, and rely on Cygwin to make their applications available on Windows. I have tried many of these projects and always found them too unstable for ...
5
votes
2answers
986 views

Functional programming: Writing a small interpreter

I'm working on a small Unix shell, and am contemplating the idea of writing a script interpreter. While reading about the subject I inevitably hear of functional programming, lambda calculus, and find ...
4
votes
2answers
277 views

Are “backwards” terminators for if and case unique to shell scripting?

In bash at least, if and case blocks are closed like this: if some-expr then echo "hello world" fi case $some-var in [1-5]) do-a-thing ;; *) do-another-thing esac as opposed to the ...
3
votes
6answers
704 views

Is it a bad practice to write shell script with many if-else statment and for loops?

I am maintaing several data process shell scripts which are full of if-else statements and for loops . I try to make the scritps tidy and easy to debug. When I read some suggestions about shell code ...
3
votes
1answer
2k views

Why no more macro languages?

In this answer to a previous question of mine about scripting languages suitability as shells, DigitalRoss identifies the difference between the macro languages and the "parsed typed" languages in ...
2
votes
1answer
205 views

When to malloc and free?

Valgrind does not report a memory leak during my actual usage, only during my scripted test that I scripted with a shell script to test my own shell. I found that I didn't have to use malloc every ...
2
votes
1answer
2k views

Why would I want to use CRaSH?

Justed stumbled across CRaSH and although it looks mighty interesting, I'm wondering why a Java developer should invest time & energy into learning (yet another) shell language. What sort of ...
2
votes
2answers
103 views

algorithm for shell language interpreter to find if a char is between quotes

Assume we have a string s (a C char *) that is a program in a language L. I want to parse L and know the following from the specification The following characters must be quoted if they are to ...
2
votes
1answer
69 views

One Script file or Multiple Script Files [closed]

I have a moderately long(for me at least) bash script file that that maintains a list of LAN users and the bandwidth each one uses. It is 199 lines with 11 functions and is already calling 3 different ...
2
votes
2answers
218 views

Recreating files from shell script or java?

I have java application which takes a file, which is created by a process running on terminal. I start the process using a small shell script. Then run the Java application and it reads the file ...
2
votes
2answers
1k views

Recommended guidelines for declaring bash/sh variables

I have been programming in BASH for a while now and the scripts that I write are starting to get more complicated. I realized that I started to bring in some habits from C/C++ and wanted to get ...
2
votes
0answers
68 views

Implementing redundant GIT backup scheme

I want to push a local repo to multiple remote GIT repositories to achieve redundancy in my backup scheme. So, let's say I plan to use Github and BitBucket to host my repositories. I have two ...
1
vote
2answers
260 views

is there a programming language designed to express data combinations? [closed]

Very often, when using the command line or just programming, you want to express some kind of combination that you end up using a for - which is often verbose. for (int i = 0; i<10; ++i) ...
1
vote
3answers
554 views

What is the best way to store configurations of shell/script code to execute later?

I am working on a tool (Python, may or may not be important) that will allow a user to maintain a configuration file containing arbitrary shell and/or language code to be executed on particular events ...
1
vote
2answers
443 views

DB API for shell scripting (any shell)

I am faced with some legacy shell scripts that run batch data processing jobs in Oracle using SQL+. For the most part, the data tier does not have to communicate back to the script with retrieved ...
1
vote
1answer
145 views

Unit testing C code?

I learnt about the check testing framework today that seems good. This far I've scripted tests that uses valgrind so that the tests both display output from the tests and from valgrind. Is there a ...
1
vote
3answers
254 views

Executing scripts in parallel based on dependency tree

We have an app that is using a fairly simple stack (Linux, PHP, Oracle, Shell Scripts, etc). We have a series of scripts that need to be executed: /scr/app1/start.sh /scr/app2/start.php ...
1
vote
0answers
90 views

Writing shell extensions in C#: What are the risks?

Raymond Chen said in 2006 and repeated in 2013: Do not write in-process shell extensions in managed code But I am perplex since there even is a library which is exclusively dedicated to writing ...
0
votes
3answers
1k views

How to set-up a simple subversion workflow

I am trying to set-up a simple SVN workflow at home. I am new to subversion (and programming) so I have been reading the official PDF documentations but still not sure about how to set-up my ...
0
votes
2answers
105 views

How is possible for a program to write on the same line?

Many programs are capable to "rewrite" on the same line, not in a STDOUT way. For example scp write the percentage or many installation programs will show you the nice rotating wheel. How it works?
0
votes
2answers
119 views

Is renaming an 'alias' for moving?

Is it true to say (on Windows and Unix\Linux\OS X) that renaming a file or directory is just an alias for moving? e.g. Are there any side effects to either which are not present on the other? Does ...
0
votes
2answers
100 views

git clone vs cp -R

I want to use an existing project as a starting point for a new project by copying or cloning it. There are at least two ways of doing this. Method 1: Copy it. cp -R /path/to/source /path/to/dest ...
0
votes
1answer
241 views

Where does the tradition of shell prompts in code snippets come from?

Most code samples I see that demonstrate shell code preface each command with $. Having a prefix makes sense, but I'm confused as to why $ is used in particular. Some other symbol, like !, that can be ...
0
votes
3answers
162 views

Shell independence in programming groups

Our programming environment is dependent upon certain environment variables being set. For example, to use distcc, one needs to define the DISTCC_HOSTS environment variable. The way we handle this is ...
0
votes
3answers
626 views

Which language is more suitable heavy file tasks?

I need to write a script (based on basic functions) to process /image/audio/video files. The process is mainly filesystem tasks and converts. The database of files has been stored by mysql. The script ...
0
votes
1answer
78 views

How did the “abnormal” options in shell commands appear?

These options which obscure me are like ps aux, route -ee, gcc -fPIC xxx, find . -name xxx and so on. The examples above aren't comprehensive. I.e., I don't think that the argument handle ...
0
votes
1answer
190 views

using pre-commit / post-merge hook script to replace configuration values

I'm having some problem developing a web application with various developers, each one has an specific configuration to work. and i would like to use the less resource cosuming approach to avoid that ...
-1
votes
0answers
27 views

dropdown style typeahead on the command line?

Is anyone aware of any tools / techniques for creating a pattern matching typeahead on the command line? This is frequently used in web UIs. How do you do it on the command line? Specifically, I am ...
-2
votes
1answer
241 views

Why is Ruby's interpreter so small? [closed]

I noticed that the filesize of Ruby's interpreter seems suspiciously small. I would have expected /bin/dash to be the smallest of all, but is 20x larger than Ruby: Interpreter Bytes ...
-2
votes
1answer
154 views

For loop and recursion for a new shell in C [closed]

I code a new shell in C, that could be done in several ways: Flex/bison, finite state machine, abstract syntax tree or just a tokenizer in C. Now I've written a for-loop that changes the condition of ...
-2
votes
1answer
132 views

How can I have a shell script log into a remote server and execute imqcmd there? [closed]

I want to write a shell script to connect to the remote server and execute a command (any linux command). I am using linux and want to prepare a shell script which can login to the virtual directory ...