find-inactive-ssh-sessions.sh add context in docs

README.md

@@ -7,7 +7,7 @@ Miscellaneous scripts for different purposes. Mostly unrelated to each other.
 
 | Category | Script & Language | Purpose & Usage |
 |:---|:---|:---|
-| Automation | [`find-inactive-ssh-sessions.sh`](bin/find-inactive-ssh-sessions.sh) <br> Shell (bash) | Find inactive (idle) SSH sessions or kill (`-k`) them.<br>`find-inactive-ssh-sessions.sh [-k] [-i seconds] [-s]`|
+| Automation | [`find-inactive-ssh-sessions.sh`](bin/find-inactive-ssh-sessions.sh) <br> Shell (bash) | Find inactive (idle) SSH sessions or kill (`-k`) them.<br>`find-inactive-ssh-sessions.sh [-k] [-i seconds] [-s]`<br>Could be used as a [workaround](https://serverfault.com/a/1162840/274176) for OpenSSH < 9.2 that did not have the [sshd_config(5)](https://man.openbsd.org/sshd_config) keywords `ChannelTimeout` & `UnusedConnectionTimeout`.|
 | Email | [`mail-prepender.sh`](bin/mail-prepender.sh) <br> Shell (bash) | Prepends (to stdin/stdout) email header strings given in as flags `i`, `I`, `a`, or `A`; after possible mbox `From` & `Return-Path` header lines. Intended as a limited `formail` replacement that ignores the nyanses of the flags and simply prepends the valid (RFC 5322, 2.2) non-empty headers keeping the other headers as is. Flags `x` & `X` are implemented. Any other flags are ignored. |
 | Git | [`git-find-commits-by-file-hash.sh`](bin/git-find-commits-by-file-hash.sh) <br> Shell (bash) | Search Git repository history for commits with SHA-256 checksum of a file. Answers the question "Has this version of this file ever been committed as the file on this path of this Git repository?" and shows a summary (`git show --stat`) of the matching commit(s). The `path` should be relative to the repository root. <br> `git-find-commits-by-file-hash.sh sha256sum path`|
 | Infosec | [`netcat-proxy.sh`](bin/netcat-proxy.sh) <br> Shell (sh) | Creates a simple persistent TCP proxy with netcat & named pipes. <br> `netcat-proxy.sh listenport targethost targetport` |

bin/find-inactive-ssh-sessions.sh

@@ -11,6 +11,9 @@ read -r -d '' USAGE << EOM
 #        Format: user tty (age)[: PID]
 #   -h   Help. Prints this and exits (ignoring all other options).
 #
+# This could be used as a workaround for OpenSSH < 9.2 that did not have
+# the sshd_config(5) keywords ChannelTimeout & UnusedConnectionTimeout.
+#
 # Author : Esa Jokinen (oh2fih)
 # Home   : https://github.com/oh2fih/Misc-Scripts
 # ------------------------------------------------------------------------------