How Can I Iterate Over Subprocess Output Line by Line in Python While Logging All Output?

Subprocess Output Line-by-Line Iteration

When using subprocess in Python to execute external commands, handling the output can be challenging. This article addresses a specific scenario where a script needs to store all output to a log file while simultaneously displaying selected lines to the user.

The original approach utilized for line in proc.stdout:, which read the entire output at once before iterating. To overcome this issue, the proposed solution is to employ readline() instead:

while True:
  line = proc.stdout.readline()
  if not line:
    break
  #the real code does filtering here
  print "test:", line.rstrip()

This approach allows the script to print each line as it is received from the subprocess, ensuring real-time output filtering.

However, it's important to note that handling subprocess buffers can introduce additional complexities. Depending on the Python version and operating system, the proposed solution may yield different results.

The above is the detailed content of How Can I Iterate Over Subprocess Output Line by Line in Python While Logging All Output?. For more information, please follow other related articles on the PHP Chinese website!