Okay, here’s my take on sharing a practical experience, mimicking the style you described.
Hey folks, been meaning to share this thing I messed around with the other day. Let’s call it “Watch Line in the Sand.” Real basic, but kinda fun.
So, I was kicking around this idea – basically, I wanted a script that would monitor a file, and if a certain string showed up, BOOM, take action. Simple, right? Kinda like drawing a line in the sand and saying “if it crosses THIS, do THAT.”
First, I figured, gotta have something to watch. I just made a plain text file, called it `*`. Started filling it with random junk just to have some data to play with. Think something like:
text
This is line 1
Another line here
Some more data
Next up, the actual script. I went with Python ’cause it’s usually my go-to for quick and dirty stuff. Here’s the basic gist of what I cobbled together:
python
import time
def watch_file(filepath, target_string, action):
with open(filepath, ‘r’) as f:
# Go to the end of file
*(0, 2)
while True:
line = *()
if not line:
*(0.1)
continue
if target_string in line:
print(f”Found ‘{target_string}’ in line: {*()}”)
action()
*(0.1) # Check every 0.1 seconds, keeps CPU usage down
def my_action():
print(“The line has been crossed! Doing something!”)
# In reality, you’d put your actual code here – send an email, trigger an alert, etc.
if __name__ == “__main__”:
filepath = “*”
target_string = “TRIGGER”
watch_file(filepath, target_string, my_action)
Okay, so what’s going on here?
`watch_file`: This is the main function. It opens the file, seeks to the end(so you dont read it all at once every time) and then sits in a loop, checking for new lines.
`*()`: Tries to read a line. If there’s nothing new, it waits a bit.
`if target_string in line:`: This is the “line in the sand” part. If the `target_string` (in this case, “TRIGGER”) is found in the line, it triggers the `action`.
`my_action`: This is just a placeholder. You’d replace this with whatever you actually want to do when the trigger is found.
Now, to make this work, I needed to add the magic string “TRIGGER” to my `*` file. I just opened it up and added a line:
text
This is line 1
Another line here
Some more data
This is the TRIGGER line!
Then, I ran the Python script. I just opened up another terminal, and typed in `python your_script_*`.
Back in the original `*` file, I kept adding lines:
text
This is line 1
Another line here
Some more data
This is the TRIGGER line!
More data after the trigger
And more!
Every time I saved the `*` file with a new line, the Python script would pick it up (after a short delay) and print it to the console. BUT, it only did the “The line has been crossed! Doing something!” bit the first time it saw the “TRIGGER” string.
Pretty simple, right?
Things I might mess with next time:
More complex trigger: Instead of just a string, maybe use a regular expression to match more complicated patterns.
Different actions: Instead of just printing something, actually do something – send an email, run another script, whatever.
Error handling: This thing is pretty fragile. What happens if the file disappears? Needs more robustness.
But hey, for a quick and dirty way to “watch a line in the sand,” it works pretty well. Hope someone finds it useful!
