From 266fdc217bf4e7f113e4c3b998a96c87dc85c4b9 Mon Sep 17 00:00:00 2001
From: koalaman <vidar@vidarholen.net>
Date: Mon, 7 Dec 2015 14:23:10 -0800
Subject: [PATCH] Created SC2095 (markdown)

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 1 file changed, 32 insertions(+)
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+## Add < /dev/null to prevent ssh from swallowing stdin.
+
+The same error applies to multiple commands, like `ffmpeg` and `mplayer`.
+
+### Problematic code:
+
+```sh
+while read -r host
+do
+  ssh "$host" "uptime"
+done < hosts.txt
+```
+
+### Correct code:
+
+```sh
+while read -r host
+do
+  ssh "$host" "uptime" < /dev/null
+done < hosts.txt
+```
+### Rationale:
+
+Commands that process stdin will compete with the `read` statement for input. This is especially tricky for commands you wouldn't expect reads from stdin, like `ssh .. uptime`, `ffmpeg` and `mplayer`.
+
+The most common symptom of this is a `while read` loop only running once, even though the input contains many lines. The is because the rest of the lines are swallowed by the offending command.
+
+To refuse such commands input, redirect their stdin with `< /dev/null`. 
+
+### Exceptions:
+
+None.
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