Question

I am trying to write a shell script that waits until the number of files in a specified directory ( say ~/fit/) has reached a predefined number. What I’ve got so far is:

limit = 10
while [ls ~/fit/ | wc -l -lt $limit]
do
  sleep 1
done

This says -lt is an invalid option to wc. I also tried

[$limit -gt ls ~/fit/ | wc -l]

but it didn’t work either. Any help is greatly appreciated.

Answer 1

A solution that minimize the use of external processes, like ls, wc and true, and manage correctly the (unusual) case of filenames containing newlines:

#!/bin/sh

nmax=10

while :; do
  n=0
  for f in ~/fit/*; do
    n=$((n+1))
  done
  [ $n -ge $nmax ] && break
  sleep 1
done

echo "Limit reached!"