Finding an Unknown Configuration File Under Time Pressure

Use package metadata first; it is faster and more accurate than a broad find. On Debian, dpkg -L smokeping lists every file the package installed, so filter for config: dpkg -L smokeping | grep -E '^/etc|conf'. To go the other way from a suspected filename, dpkg -S /etc/smokeping/config shows which package owns it. Second, ask systemd: systemctl cat smokeping.service prints the unit and usually reveals ExecStart= with a -c or --config path; systemctl status gives the running command line. Third, inspect the running process with ps -ef | grep smokeping to see the actual config argument. Fourth, use documentation: man smokeping, man -k smokeping (or apropos smokeping) to find related pages, and ls /usr/share/doc/smokeping/ for examples, README, and changelog. If locate is installed and its database is current, locate smokeping | grep /etc is fast. Only then use a scoped find: find /etc /usr/share/doc -iname '*smokeping*' 2>/dev/null. Avoid find / because /proc and /sys produce errors and slow scans, and mounted network filesystems may hang. After editing, validate with the service's own test, then systemctl reload smokeping and check journalctl -u smokeping -n 50.

Man pages are divided into numbered sections. Section 1 is user commands, section 5 is file formats and configuration syntax, and section 8 is system administration commands. The same name can appear in more than one section. man 5 smokeping.conf asks for the file-format page specifically; without the number, man picks the first match, often the command page. If you do not know the exact page name, man -k smokeping searches the whatis database for names and short descriptions, and whatis smokeping.conf shows the one-line summary. If the page is missing, the documentation package may not be installed; on Debian check dpkg -L smokeping | grep man and install the package or its docs if appropriate. Also look in /usr/share/doc/smokeping/, which often contains HTML or README files. If you see a page but the config syntax is unclear, man 5 for the specific file and the examples under /usr/share/doc together are more reliable than guessing. Remember man man explains the section layout, and man -a name shows every section's page in sequence. In a change window, confirm the page's version matches the installed package rather than relying on a web copy.

Under the Filesystem Hierarchy Standard, /etc is for host-specific configuration; the smokeping config belongs in /etc/smokeping/, never in /usr. /usr is shareable, read-only data: binaries, libraries, and documentation. Editing /usr/bin/smokeping or a file under /usr/share is wrong because package upgrades overwrite it and because /usr may be mounted read-only or shared between hosts. /var/log holds variable log data, /var/lib holds persistent state such as databases, /srv holds data served to users, and /opt is for add-on software trees. If the setting is a local override, prefer a file in /etc included by the main config rather than editing a packaged default. Back up the original with cp -a file file.bak in the same directory, keep a note of the change, and use systemctl reload rather than restart if the daemon supports it. This preserves the package's files and makes rollback and audits straightforward.