I dont really understand whats going on and cant see the difference:
I'm downloaded the base64.exe for creating base64 text under windows. i copied it to C:\Windows\ because its in the %PATH% variable.
Now i want to try it: echo Hello | base64 works great. Okay i dont need to append .exe and as far as i know i dont need to do it also with .bat and .com files.
But now i have some cygwin tools installed and for example tried which base64, which doesnt work, because it says that base64 is not in path. Then i typed in which base64.exe and got C:\Windows.
So my question is now: when i need to use .exe and when i dont? Is it only when i'm using cygwin tools that i need to append .exe?
Cygwin is a shell which emulates UNIX behaviour. UNIX doesn't know anything about .exe, thats why Cygwin can't find base64.exe. Under UNIX, binaries are stored without an extionsion added to their filename, e.g. just base64.
Windows CMD automatically appends .bat, .com, .exe and the like to your file names. Cygwin does not. So if you are using a linux shell you have to append it manually.
Since Cygwin is aware that it always runs under Windows it might append .exe if you want to perform certain actions in the shell itself (e.g. opening a file), to behave more friendyl to Windows users who expect this behaviour. However programs running under Cygwin might not integrate those features since they were mainly devoloped for usage under UNIX. That could be a reason why which base64 fails.
Related
When compiling/interpreting a program from the command prompt, how does the command prompt know where to find the requested compiler/interpreter?
Are these files stored in a specific place or something like that? I'm just about getting a hang of high-level programming, but I find it pretty hard to wrap my head around what happens under the hood.
There are two parts: Where to find the file just from it's filename, and what to do with it.
Where files (programs) are searched if just the name is entered:
Windows (CMD):
There is a variable %PATH% which has a list of ;-separated directories, eg. C:\Windows;C:\Windows\system32;C.\somethingelse. It is saved somewhere in the registry and can be set either in CMD itself or with a GUI somewhere in the OS configs.
Linux etc. (Bash and many more):
Similar, there is a variable $PATH which can be set at least in the shell and various config files, and the entries are separated by :, eg. /bin:/usr/bin/even/more. Priority is from left to right.
Additionally, some shells (eg. Bash) cache lookup results in their own implementation-specific way (depending on the configuration), because it's faster than having to check every directory in the path variable (at least if the searched program is in the last dir, everything has to be checked).
What to do with the file once it's found:
Windows:
In Windows, everything works with the filename suffix.
.exe and some others are native programs to start.
.bat is a shell script which is executed like it's manually written to the shell.
For every other suffix, it's configurable which program belongs to the suffix (stored in the registry, how to comfortably change it depends heavily on the used Windows version). Eg. you could say that .py belongs to your Python interpreter, the a file foo.py will start the interpreter. Btw., the same suffix-program configuration is usen when a file is double-clicked in the GUI file explorer, and of course program installers can add their entries too without the user having to do it.
Linux:
For Linux, the suffix is not as important. The first relevant thing is a binary (yes/no) flag x (x like executable) which exists for each file on the file system, just like file name, creation timestamp etc.etc.
If the x flag is set to yes:
Linux tries to detect what kind of program it is from the content. The difference between a native compiled binary program and a not-compiled script of some scripting language is pretty clear.
A native linux program is started by the kernel, like expected. Additional binary program types could be configured, eg. there is the Wine software which runs some Windows programs on Linux, and one could add a specification how Windows exe`s can be recognized inside and that they should be started with Wine.
For a text file with the x flag, the next step is to look at the first line, which should start with a '#!' (called shebang), followed by the path of the interpreter (eg. #!/bin/bash). Shell scripts (like the bat files on Windows) are realized this way, but it's not limited to classical shell scripts: Nothing prevents anyone from making a #!/bin/python script which Python content (of course, Python has to be installed for this to work).
If the x flag is set to no:
Shells like bash with usual configuration won't do anything, independent if it is a real program just without flag or a jpg image etc. For the GUI file managers:
Again, the content (and possibly the file name suffix too) is inspected to get the type, like jpg images, mp3 music, C++ source code etc.etc. (Linux knows pretty many types), and then the fitting program is looked up in a list configurable by the user and/or program installations (mime file type id <-> program).
...
Note that in the case of eg. Python scripts (which are just normal text files, not something for the kernel to work with), it can be done with and without x flag: With flag and a shebang line, or without flag and a matching mime list entry. In the "without flag" case, the shebang won't hurt if it is there, because Python (and many other scripting languages) consider it a comment because of the #.
Regarding interpreters on unix-based systems, lots of scripts start with a so-called shebang or hashbang (#! on the first line of the script) that tells what interpreter to invoke, see https://en.wikipedia.org/wiki/Shebang_%28Unix%29 .
When you enter something like some-program some-arguments, the shell will look through each directory listed in the environment variable $PATH for an executable file named some-program (on Windows it's %PATH% and some-program.exe).
This is not specific to compilers and interpreters - it happens whether some-program is gcc, python, firefox or notepad.
Our Apache web server works in a Linux environment.
The cgi executables are called via a sh file (for example /cgi-bin/iwsblogin.sh).
The call "/cgi-bin/iwsblogin.sh" is in an html file.
Now I want to make a development and testing environment for this web server on windows.
I do not want to change the calls in the html files from "iwsblogin.sh" to "iwsblogin.bat" just for testing purposes.
Is there a way to configure windows in such a way, that files with the extension ".sh" are treated as executables the same way as ".bat" and ".exe" files?
The contents of this .sh file is for example:
- ms dos commands for setting some environment variables.
- Path of an exe file which should be called.
I know that there exist similar questions on stackoverflow where user suggest using cygwin, but this is NOT an option for me!
Thanks alot in advance
There are some ways to do this.
If the .sh file works when you rename it to .bat, you can use "run as" and select C:\Windows\System32\cmd.exe as default program
Use a sh emulator. For example, msysgit includes one or you can use cygwin (possibly the same source?).
I know you don't want to use cygwin, but why not? Please explain why this isn't an option. It is hard to look for an answer if we don't know why regular answers won't work.
I need to execute a command like vlc 舨.avi programatically on Windows. When done directly in cmd.exe this works just fine, proving that VLC has the capability to recognize unicode arguments. However, I'm having trouble putting this in a script and having it work.
Has anyone done this successfully? I would love to do this in Ruby (I have 1.9.2) but Python-win32, Perl-win32, batch, .cmd, VB/W/JScript are all options. Target O/Ses are XP and Vista.
It's most likely an encoding issue.
Encoding in command prompts and in windows is not always the same. If your script in Notepad, then execute it, you may end up with the filename being converted to unicode differently hence the error.
Somehow, you'll have to make sure that the encoding is correct, maybe by saving you batch file as Unicode text file? Would that work?
I want to set an alias to my installation of firefox so I can easily start a web page, the problem is that I dont want the script to be system dependent.
Namely I want it to be able to run on a linux distribution where the command to start firefox is already mapped to 'firefox' and can easily be run that way through bash, but on my windows machine I cant seem to get it to assign to the same variable.
I saw that I could set it to '%firefox%' via the set command but that's not quite what I want.
I believe creating aliases is possible on a windows environment because the version of svn that I use auto-installed and was able to assign itself to 'svn'. Anyone know what was involved in them being able to get their alias working, or a similar way to alias a command?
If you include your Firefox path in the %PATH% environment variable, you can start FF with "firefox". Under Windows, you should edit the system-wide settings (see this link).
AFAIK, there is nothing similar to aliases under DOS/Windows (except the %firefox% way you mentioned, too). The 'svn' command you talked about most likely is the same thing, a 'svn.exe' and its path included to %PATH%.
This is a bit restrictive, as you can only use the original filename to launch a program, but you can work around this by creating a batch file in the program's path that launches the program, f.e. a FF.BAT that contains "firefox %1".
Alternatively, you can place a batch file in a path that already is in %PATH%, f.e. the Windows directory. That way, you don't have to modify %PATH%.
I have a shell extension installed into the filesystem by adding ".{CLSID}" to the folder name. The Shell Extension is like the .zip extension (allowing you to see files). Explorer handles it fine, but how do I get other program to recognize the sub files/folder (programs like command shell). I navigate to the directory with the shell and it shows the empty folder (also, it doesnt strip away the clsid). Is there some way to implement that functionality? Do I have to install the extension in a different way?
Thanks!
chacham15
If I remember correctly, there is no documented way to add an extension to the windows cli shell (cmd.exe).
There is an add on shell for windows called 4NT that is extensible.
That said, you'll still end up writing scripts if I understand your question correctly.