Fix: expr: syntax error while running rkhunter

If you’re trying to run rkhunter check on your server and finding expr: syntax error for all binaries, it might be due to outdated file properties database.

Run the following command to fix it:

rkhunter –propupd –update

After updating the file properties database, you must get rkhunter working fine again.

Here is some more information about –propupd option

–propupd [file | directory | Update the entire file properties database,
package]… or just for the specified entries