Bash script logic fails occaisionally-CodePudding

This script checks a file size. If it is under the "minimum size" it should run the python script. However if it is over the minimum size the script should do nothing and exit. The problem that I am having is that sometimes when the file is over the minimum size the python script still runs. What am I not seeing?

#!/bin/bash
    todays=$(date  %m-%d-%Y)
    file_prefix=./csv/data_
    file_suffix=.csv
    file=${file_prefix}${todays}${file_suffix}
    echo $file
    minimumsize=64
    actualsize=$(wc -c <"$file")
    echo 
    if [ "$actualsize" -ge "$minimumsize" ]; then
        echo size is over $minimumsize bytes
    else
        echo size is under $minimumsize bytes
        #Script to run if filesize is under minimum size
        /usr/bin/python3 /home/shannon/scripts/myscript.py 
    fi

CodePudding user response：

It may be that the file is occasionally missing. You can solve that most easily by substituting a 0 size if the wc or stat fails. I'd recommend stat generally, since it doesn't actually read the file, which can be useful if the file is large or if the script hasn't got permission to read the file.


#!/bin/bash

file=./csv/data_$(date  %m-%d-%Y).csv
minimumsize=64
actualsize=$(stat -c%s $file 2>/dev/null || echo 0)
echo $file
echo

if [ $actualsize -ge $minimumsize ]; then
    echo size is over $minimumsize bytes
else
    echo size is under $minimumsize bytes

    # Script to run if filesize is under minimum size
    /usr/bin/python3 /home/shannon/scripts/myscript.py 
fi