Question

Can anyone help me return the correct value from a bash script function?

Here’s my function that should return first (and only) line of the file passed as an argument:

LOG_FILE_CREATION_TIME()
{
    return_value=`awk 'NR==1' $1`
    return return_value
}

And here’s my call of that function in the other script:

LOG_FILE_CREATION_TIME "logfile"
timestamp=$?
echo "Timestamp = $timestamp"

I always get some random values with this code. If, for example, there’s a value of 62772031 in the “logfile”, I get

Timestamp = 255

as an output. For some other values in the file, I get other random values as a return value, never the correct one.

Any ideas?

Answer 1

The exit code is limited to 0 - 255, you cannot use it for a timestamp.

Echo your timestamp instead, since you don’t seem to be outputing anything else; this ought to be fine?

LOG_FILE_CREATION_TIME()
{
    # If you want to do some more stuff, you might want
    # to use the intermediate variable as you first did.
    awk 'NR==1' $1
}

timestamp=$(LOG_FILE_CREATION_TIME "logfile")
echo "Timestamp = $timestamp"

You might have simplified the function in your example, because if all you wanted was the first line, why not use head -1 logfile instead?