R – How to extract a full path from the PATH environment variable

batch-filecmdscriptingwindows

I want to extract a full path from the PATH environment variable with native cmd tools. Consider the following PATH content:

C:\Program Files\Windows Resource Kits\Tools\;C:\Perl\site\bin;C:\Perl\bin;C:\WI
NDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;c:\Program Files\Microsoft SQ
L Server\90\Tools\binn\;C:\WINDOWS\system32\WindowsPowerShell\v1.0;C:\Program Fi
les\Microsoft SQL Server\80\Tools\Binn\;C:\Program Files\Microsoft SQL Server\10
0\DTS\Binn\;C:\Program Files\Microsoft SQL Server\100\Tools\Binn\;c:\program fil
es\nmap\;C:\Program Files\WinRAR\;C:\Program Files\QuickTime\QTSystem\;C:\Progra
m Files\hydra-5.4-win\;C:\Program Files\john1701\run;C:\dig;;C:\cygwin;C:\wamp\b
in\mysql\mysql5.0.45\bin;C:\Program Files\MySQL\MySQL Server 5.0\bin;C:\Program
Files\Tail4win;C:\Program Files\Overlook Fing 1.1\bin

I want to extract only the following path:

C:\Program Files\MySQL\MySQL Server 5.0\bin;

Is FOR capable of such thing?

Best Answer

You can use for to tokenize at ; but you need to take care of paths that have a ; in them (and thus need quotes). All in all I'd say you'd build a pretty brittle solution with pretty much code at this point.

If you want to know where a certain executable is, then

for %%i in ("mysql.exe") do @echo.%%~$PATH:i

will tell you that (or not, if it's nowhere in the PATH).

UPDATE: Ok, I got it. One nasty little batch file follows:

@echo off
setlocal enabledelayedexpansion enableextensions
set p=%PATH%
:loop
for %%i in ("notepad.exe") do call :setvar "%%~$p:i"
if not :%x%:==:: (call :clearpath & goto loop)
goto :eof

:setvar
    set x=%~1
goto :eof

:clearpath
    echo %x%
    for %%x in ("!x!") do set d=%%~dpx
    set d=!d:~,-1!
    set p=!p:%d%=!
goto :eof

This will print all matching paths from PATH where notepad.exe was found (the first program I know off the top of my head to be in two places here). Adapt accordingly for your problem.

:clearpath simply deletes the found path from the variable and then we try matching again, until no match is left.

That said, this is still very un-pretty.

New answer, powershell

TCP

Get-Process -Id (Get-NetTCPConnection -LocalPort YourPortNumberHere).OwningProcess

UDP

Get-Process -Id (Get-NetUDPEndpoint -LocalPort YourPortNumberHere).OwningProcess

Old answer, cmd

 C:\> netstat -a -b

(Add -n to stop it trying to resolve hostnames, which will make it a lot faster.)

Note Dane's recommendation for TCPView. It looks very useful!

-a Displays all connections and listening ports.

-b Displays the executable involved in creating each connection or listening port. In some cases well-known executables host multiple independent components, and in these cases the sequence of components involved in creating the connection or listening port is displayed. In this case the executable name is in [] at the bottom, on top is the component it called, and so forth until TCP/IP was reached. Note that this option can be time-consuming and will fail unless you have sufficient permissions.

-n Displays addresses and port numbers in numerical form.

-o Displays the owning process ID associated with each connection.

Python – How to install pip on Windows

Python 2.7.9+ and 3.4+

Good news! Python 3.4 (released March 2014) and Python 2.7.9 (released December 2014) ship with Pip. This is the best feature of any Python release. It makes the community's wealth of libraries accessible to everyone. Newbies are no longer excluded from using community libraries by the prohibitive difficulty of setup. In shipping with a package manager, Python joins Ruby, Node.js, Haskell, Perl, Go—almost every other contemporary language with a majority open-source community. Thank you, Python.

If you do find that pip is not available when using Python 3.4+ or Python 2.7.9+, simply execute e.g.:

py -3 -m ensurepip

Of course, that doesn't mean Python packaging is problem solved. The experience remains frustrating. I discuss this in the Stack Overflow question Does Python have a package/module management system?.

And, alas for everyone using Python 2.7.8 or earlier (a sizable portion of the community). There's no plan to ship Pip to you. Manual instructions follow.

Python 2 ≤ 2.7.8 and Python 3 ≤ 3.3

Flying in the face of its 'batteries included' motto, Python ships without a package manager. To make matters worse, Pip was—until recently—ironically difficult to install.

Official instructions

Per https://pip.pypa.io/en/stable/installing/#do-i-need-to-install-pip:

Download get-pip.py, being careful to save it as a .py file rather than .txt. Then, run it from the command prompt:

python get-pip.py

You possibly need an administrator command prompt to do this. Follow Start a Command Prompt as an Administrator (Microsoft TechNet).

This installs the pip package, which (in Windows) contains ...\Scripts\pip.exe that path must be in PATH environment variable to use pip from the command line (see the second part of 'Alternative Instructions' for adding it to your PATH,

Alternative instructions

The official documentation tells users to install Pip and each of its dependencies from source. That's tedious for the experienced and prohibitively difficult for newbies.

For our sake, Christoph Gohlke prepares Windows installers (.msi) for popular Python packages. He builds installers for all Python versions, both 32 and 64 bit. You need to:

For me, this installed Pip at C:\Python27\Scripts\pip.exe. Find pip.exe on your computer, then add its folder (for example, C:\Python27\Scripts) to your path (Start / Edit environment variables). Now you should be able to run pip from the command line. Try installing a package:

pip install httpie

There you go (hopefully)! Solutions for common problems are given below:

Proxy problems

If you work in an office, you might be behind an HTTP proxy. If so, set the environment variables http_proxy and https_proxy. Most Python applications (and other free software) respect these. Example syntax:

http://proxy_url:port
http://username:password@proxy_url:port

If you're really unlucky, your proxy might be a Microsoft NTLM proxy. Free software can't cope. The only solution is to install a free software friendly proxy that forwards to the nasty proxy. http://cntlm.sourceforge.net/

Unable to find vcvarsall.bat

Python modules can be partly written in C or C++. Pip tries to compile from source. If you don't have a C/C++ compiler installed and configured, you'll see this cryptic error message.

Error: Unable to find vcvarsall.bat

You can fix that by installing a C++ compiler such as MinGW or Visual C++. Microsoft actually ships one specifically for use with Python. Or try Microsoft Visual C++ Compiler for Python 2.7.

Often though it's easier to check Christoph's site for your package.