shang-lin

#!/usr/bin/env python3

""" Checks if a password has been pwned using the haveibeenpwned.com API.
"""

import getpass
import hashlib
import requests

def get_matching_list(hash_prefix):

shang-lin

# myfile.csv is a CSV export of a Google sheet. that contains name, email, and affiliation .
# The first three lines are headings and boilerplate. "-n +4" tells tail to only display line 4 and later.
# The cut command extracts the second column (email addresses) using ',' as the delimiter.
# tr transforms the newlines into commas to create a comma-separated list of only email addresses.
tail -n +4 myfile.csv  | cut -d ',' -f 2  | tr '\n' ','

shang-lin

# ls -s displays the size of files, in blocks, followed by the file name.
# For convenience, I am setting the block size to 1024 bytes, or 1 kilobyte.
# The output of ls -s is piped to an awk command that incrementally adds the file sizes and displays the total.
ls --block-size=1024 -s /path/to/files | awk '{ total += $1 }; END { print total }'

shang-lin

Formatting strings

printf "%s %d %d %d\n" "Testing" 1 2 3

Output:

Testing 1 2 3

Remove whitespace

shang-lin

Git Recipes

Removing a file from the repository

git rm filename

Removing a file from the repository but keeping the copy in the current working directory

git rm --cached filename

Removing the entire history of a file

shang-lin

Google search results used to include a link to a cached version, but alas, that is no more. What should you do if a page has disappeared or changed? Try this URL to search the Google cache:

http://webcache.googleusercontent.com/search?q=cache:http://example.com/

Replace example.com with the actual URL you want.

shang-lin

# Deletes empty (size 0) files from the directory provided as a command-line
# argument. Currently does not descend into subdirectories.

# Created August 2005.
# author: Shang-Lin Chen

use File::stat;
use File::Copy "move";

$num_args = @ARGV;

shang-lin

#!/bin/bash

# clear_ipc
#
# Delete the IPC objects created by a user. The user and IPC type are specified on the command
# line.
#
# usage: clear_ipc username type

USERNAME=$1

shang-lin

# Demo of how to process files in Perl.

# Replace with the actual name of the file.
my $file_name = "myfile.txt";

# Open the input file read-only.
open(IN, "<$file_name") or die "Cannot open  $file_name\n";
# Open the output file for writing.
open(OUT, ">outputfile.txt") or die "Cannot open output file\n";