Reading command line password argument with "ps" in Linux

Mon, 04 Mar 2019 15:21:11 +0000

Introduction:

I was recently reading an article online about some methods to hide password argument from system status programs like “ps” or “top” in Linux and I decided to take a closer look.

I’ve created a simple Python script that accepts a single argument for password, let’s run it:

$ ./program.py -p secret123 &
[1] 18200
Sleeping for 600s. PID: 18200

Now, we check the output from “ps”:

$ ps -lfp 18200
F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME TTY TIME CMD
0 S root 18200 16045 0 80 0 - 32500 poll_s 12:26 pts/2 00:00:00 python3 ./program.py -p secret123

Hmm, that’s not good, any user on the system can ready our password now but if we check the help menu for our program, it looks like it can accept password either from the argument or environment variable:

How to determine the number of physical CPUs on Linux

Tue, 17 Jul 2012 15:51:00 +0100

The /proc/cpuinfo file contains information about the CPUs installed on your computer however it’s quite confusing when you have to deal with multi-core processors.

- list number of physical CPUs:

$ cat /proc/cpuinfo | grep "physical id" | sort | uniq | wc -l
1

- number of cores:

$ cat /proc/cpuinfo | grep "cpu cores" | uniq
cpu cores : 2

- how many virtual processors:

$ cat /proc/cpuinfo | grep "^processor"
processor : 0
processor : 1