executing shell commands in python

execute_shell_in_python.py

# ref: https://janakiev.com/blog/python-shell-commands/

# 1. using os
import os
output = os.system('ls -l')
print(output)

# 2. using subprocess
import subprocess

# this example writes a dictionary (dict_obj) to a text file
put = subprocess.Popen(["hdfs", "dfs", "-put", "-", file_path], 
                    stdin=subprocess.PIPE, text=True)

put.stdin.write(json.dumps(dict_obj))
put.stdin.close()
put.wait()

# this example captures output using 'cat'
file_current = subprocess.check_output(["hadoop", "fs", "-cat", file_path])
list_obj = filter(None, file_current.split(sep))  # split into array  

# leverage an existing bash script
  # first, make sure bash script is executable
d = 'path/to/dir'
subprocess.call(f'./erase_files_in_dir.sh {d} png', shell=True)