Shell Programming and Scripting

Hello All,

I am trying to write a script that will only continue executing my script if a file exits. I know the directory of the file, so its just a matter of seeing if the file exists yet. If the file has not yet been created, I want the script to wait 10 minutes (600 seconds) and try again. I was thinking of using the "until" command somehow, but can't figure it out. Please help!

Jose

Which shell? Here is a possibility using ksh:

Code:

myfile=/path/to/file
while true
 do
  if [[ -a $myfile ]]; then
    echo "$myfile exists!"
  else
    sleep 600
  fi
done

Excellent! I guess if I want it to validate if more than one file exists I would do the following:

myfile=/path/to/file
myfile2=/path/to/second/file

while true
do
if [[ -a $myfile && -a $myfile2]]; then
echo "$myfile exists!"
rest of code
else
sleep 600
fi
done

Thank you.

Jose

You can also do :

Code:

required_files='/path/to/file1 /path/to/file2 /path/to/file3'
interval=600

for file in ${required_files}
do
   until [[ -a "${file}" ]]
   do
      sleep ${interval}
   done
done

echo "All required files found."

Jean-Pierre.

Thank you. I'm assuming that

until [[ -a "${file}" ]]

will keep looping until it finds all files in required_files? Also, I'm guessing the rest of the code comes after the loops (after the last done statement). Thanks.

Jose

yes .. u r correct .. be sure that the file which u r checking for, is stable. i.e if u r getting the file at runtime then the condition " if [ -a $filename ] " will be successful even when the file is being copied in the directory, where u r looking the file for.

Quick question then. Why doesn't this code work? It keeps giving me a syntax error:

";" unexpected

Can this instance of the if statement only validate two conditions about the same file, and not check existence of one file and then existence of another?

myfile=/path/to/file
myfile2=/path/to/second/file

while true
do
if [[ -a $myfile && -a $myfile2]]; then
echo "$myfile exists!"
echo "$myfile2 exists!"
rest of code
else
sleep 600
fi
done