CODEWITHSUNDEEP
unix
Pooja25
Pooja25

Reputation: 326

How to keep polling file in a directory till it arrives in Unix

I want to keep polling file till it arrives at the location for 1 hour.

My dir : /home/stage

File Name (which I am looking for): abc.txt

I want to keep polling directory /home/stage for 1 hour but within the 1 hour if abc.txt file arrives then it should stop polling and should display the message file arrived otherwise after 1 hour it should display that file has not arrived.

Is there any way to achieve this in Unix?

Upvotes: 6

Views: 16824

Answers (5)

sabya
sabya

Reputation: 109

Here some answer with retry: 

cur_poll_c=0
echo "current poll count= $cur_poll_c"

while (($cur_poll_c < $maxpol_count)) && (($SECONDS < $end_time))
do
  if [[ -f $s_dir/$input_file ]]
  then
    echo "File has arrived...
do some operation...
sleep 5    
    exit 0
  fi
  sleep $interval
echo "Retring for $cur_poll_c time .."
cur_poll_c=`expr $cur_poll_c+1`;
done

Upvotes: 0

devnull
devnull

Reputation: 123498

The following script should work for you. It would poll for the file every minute for an hour.

#!/bin/bash
duration=3600
interval=60
pid=$$
file="/home/stage/abc.txt"

( sleep ${duration}; { ps -p $pid 1>/dev/null && kill -HUP $pid; } ) &
trap "echo \"file has not arrived\"; kill $pid" SIGHUP

while true;
do
  [ -f ${file} ] && { echo "file arrived"; exit; }
  sleep ${interval}
done

Upvotes: 4

twalberg
twalberg

Reputation: 62379

Another bash method, not relying on trap handlers and signals, in case your larger scope already uses them for other things:

#!/bin/bash
interval=60
((end_time=${SECONDS}+3600))

directory=${HOME}
file=abc.txt

while ((${SECONDS} < ${end_time}))
do
  if [[ -r ${directory}/${file} ]]
  then
    echo "File has arrived."
    exit 0
  fi
  sleep ${interval}
done

echo "File did not arrive."
exit 1

Upvotes: 16

Marco
Marco

Reputation: 879

Here's an inotify script to check for abc.txt:

#!/bin/sh

timeout 1h         \
  inotifywait      \
    --quiet        \
    --event create \
    --format '%f'  \
    --monitor /home/stage |
    while read FILE; do \
      [ "$FILE" = 'abc.txt' ] && echo "File $FILE arrived." && kill $$
    done

exit 0

The timeout command quits the process after one hour. In case the file arrives, the process kills itself.

Upvotes: 3

Noufal Ibrahim
Noufal Ibrahim

Reputation: 72755

You can use inotify to monitor the directory for modifications and then check to see if the file is abc.txt. The inotifywait(1) command lets you do this directly from the command line in a shell script. Check the man page for details. This is notification based.

A poll based thing would be a loop that checks to see if the file exists and if not, sleep for a period of time before checking again. That's a trivial shell script too.

Upvotes: 1

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