Is there an elegant and more Python-like way to check if a package is installed on Debian?
In a bash script, I'd do:
dpkg -s packagename | grep Status
Suggestions to do the same in a Python script?
This is a pythonic way:
import apt
cache = apt.Cache()
if cache['package-name'].is_installed:
print "YES it's installed"
else:
print "NO it's NOT installed"
A slightly nicer, hopefully idiomatic version of your bash example:
import os, subprocess
devnull = open(os.devnull,"w")
retval = subprocess.call(["dpkg","-s","coreutils"],stdout=devnull,stderr=subprocess.STDOUT)
devnull.close()
if retval != 0:
print "Package coreutils not installed."
dpkg -s will also return successfully (with a zero exit) if a package is in the state deinstall ok config-files, i.e. the package is not installed.This is some code that would give you a neat way to display if the package is installed or not (without triggering a messy error message on the screen). This works in Python 3 only, though.
import apt
cache = apt.Cache()
cache.open()
response = "Package Installed."
try:
cache['notapkg'].is_installed
except KeyError:
response = "Package Not Installed."
print(response)
If you are checking for the existence of a package that installs a Python module, you can test for this from within a dependent Python script - try to import it and see if you get an exception:
import sys
try:
import maybe
except ImportError:
print "Sorry, must install the maybe package to run this program."
sys.exit(1)
I needed a cross-platform compatible solution so I ended up using which.
import subprocess
retval = subprocess.call(["which", "packagename"])
if retval != 0:
print("Packagename not installed!")
Although it's not as pythonic as the above answers it does work on most platforms.
Have a look at commands. It's very useful for running things on the command line and getting the status.
Otherwise, I'm sure there is some library that will let you interact with apt. python-apt might work but it's a bit raw. Just capturing the command line seems easier.
commands is deprecated!Inspired by the previous answers, this works nicely for both Python 2 and Python 3 and avoids try/catch for the key error:
import apt
package = 'foo' # insert your package name here
cache = apt.Cache()
package_installed = False
if package in cache:
package_installed = cache[package].is_installed
import apt gives the error: ModuleNotFoundError: No module named 'apt'. What would be the most proper solution to that?I had the same doubt. Searched every corner in the Internet but couldn't find it. But finally after some Experiments I DID IT!!.
import ospackagename = "figlet" # Type in your package nameos.system("dpkg -s "+packagename" | grep Status")To type in any terminal using python codes:
import osos.system("YOUR TERMINAL COMMAND HERE")def test_dpkgInstalled(packageName): return (os.system("dpkg -s " + packageName + "> /dev/null 2>&1")) == 0