Question

I do something like

wget --user=userName --password=passWord  --timestamping https://url.to/a/file.csv.gz
gzip -cd file.csv.gz > file.csv

(not tested)

Please note that the server requires authentication.

The file will only be downloaded, if it’s newer than the local file. This is good.

However, also line 2 should only be executed if the remote file is newer than the local file.

How can I do that?

Answer 1

Just test to see if the modification time of the file.csv.gz is newer than the file.csv.

On Linux:

if [ $(stat -c '%Y' file.csv.gz) -gt $(stat -c '%Y' file.csv) ]; then
    gzip -cd file.csv.gz > file.csv
fi

On BSD (like Mac OS X):

if [ $(stat -f '%m' file.csv.gz) -gt $(stat -f '%m' file.csv) ]; then
    gzip -cd file.csv.gz > file.csv
fi

Other systems may have different arguments to stat; check man stat on your system, or help stat if it’s a shell builtin.