1. Sudo Command
You can check the sudo configuration file syntax using the visudo command, which supports a --check or -c command line option to only validate a file without an edit. The -f option displays the error message and opens the file for editing:
$ sudo visudo -c /etc/sudoers: parsed OK /etc/sudoers.d/README: parsed OK
$ visudo -h visudo - safely edit the sudoers file usage: visudo [-chqsV] [[-f] sudoers ] Options: -c, --check check-only mode -f, --file=sudoers specify sudoers file location -h, --help display help message and exit -q, --quiet less verbose (quiet) syntax error messages -s, --strict strict syntax checking -V, --version display version information and exit
$ sudo visudo -V visudo version 1.8.31 visudo grammar version 46