How to execute a command using and log its output using logging.info in python

Question

I want to execute a command and then log its output to a log file using logging.info

I am currently using

cmd = """var=$(cat ip.txt | head -1 | sed 's/[^|]//g' | awk '{ print length }')"""
logging.info(cmd)
process = os.popen(cmd)
processClose = process.close()


logging.info($var)

but it gives me an error as $ is an invalid syntax.

I want the output in the log file to print the value of the variable (var)

Answer 1

The below method of execution works with logging.info

success = sp.call(cmd, stdout=open('temp_log', 'w'), stderr=open('temp_err_log', 'w'), shell = True)
outText = open('temp_log').readlines()
outText = ''.join(outText)
logging.info('Dump stderr:\n%s'%(outText))

Answer 2

$var is invalid in your code. It is invalid because the process space in which is was created is gone.

Try this:

    import subprocess
    cmd = "cat ip.txt | head -1 | sed 's/[^|]//g' | awk '{ print length }'"
    p = subprocess.Popen([cmd,], stdout=subprocess.PIPE, shell=True)
    p.stdout.readline()

Hope this helps.