Author Archives: Linuxgal

Add line numbers to a file (Four digits, leading zeros, separated by a colon): nl -i1 -s’: ‘ -nrz -w4 cotus.txt awk ‘{printf”%04d: “,NR;print}’ cotus.txt Oh wait, you don’t want to count the blank lines? awk ‘/[^ ]/{printf”%04d: “,++n}{print}’ cotus.txt … Continue reading →

Print line numbers of matches with #fgrep fgrep -n Revenue cotus.txt

Convert a JPG to a 4-bit per pixel BMP: djpeg -colors 16 teresita.jpg > teresita16.bmp

Calculate absolute magnitude from visual magnitude for Sirius and Tau Ceti #!/usr/bin/python3 import math vmag = float(input(“Visual magnitude?: “)) dist = float(input(“Distance in light-years?: “)) amag = vmag-5*((math.log(dist/3.26156)/math.log(10))-1) print (“Absolute magnitude=”,amag)  

Okay, here’s a way ChatGPT can shine, teaching LaTeX : R_{\mu\nu} – \frac{1}{2} g_{\mu\nu} R + \Lambda g_{\mu\nu} = \frac{8\pi G}{c^4} T_{\mu\nu}

Plot a function as a contour map #!/usr/bin/python3 import matplotlib.pyplot as plt import numpy as np X, Y = np.meshgrid(np.linspace(-4, 4, 512), np.linspace(-4, 4, 512)) Z = (1 – X/2 + X**4 + Y**3) * np.exp(-X**2 – Y**2) * (1 … Continue reading →

Plot city population as a pie chart for Washington cities with more than 100,000 people #!/usr/bin/python3 import matplotlib.pyplot as plt labels = ‘Seattle’, ‘Spokane’, ‘Tacoma’, ‘Vancouver’, ‘Bellevue’,’Kent’, ‘Everett’, ‘Renton’, ‘Spokane Valley’, ‘Federal Way’ sizes = [737015, 228989, 219346, 190915, 151854, … Continue reading →

Use grep to find adjacent duplicate words in standard input: nl gettysburg.txt | grep -E “(\b\w+\b)\s+\1”

Deal four hands of five cards #!/usr/bin/python numbers= [‘A’, ‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’, ’10’, ‘J’, ‘Q’, ‘K’]*4 suits=[‘h’,’d’,’c’,’s’]*13 cards=[x+y for x,y in zip(numbers, suits)] import random random.shuffle(cards) print cards[1:6];print cards[7:12];print cards[13:18];print cards[18:23]  

#Curl #Python Get a list of links to Ukraine news non-interactively: #!/usr/bin/python3 import re, sys list = re.findall(r”https?:\S+”, sys.stdin.read()) for m in list: print (m, end=”\n”) print() —- curl https://www.bing.com/news/search?q=ukraine | ./url.py | sort | uniq | sed ‘/microsoft/d’