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--- bash:shellcheck [2016/10/17 14:21] – created peter
+++ bash:shellcheck [2020/07/15 09:30] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== Bash - ShellCheck ======
+====== BASH - ShellCheck ======
 [[https://github.com/koalaman/shellcheck|ShellCheck]] helps to identify a lot of potential issues in your shell scripts.
@@ Line 13: / Line 13: @@
 rm -rf "$dir"
 </code>
+----
 ===== More Bad Code Examples =====
-===== Common beginner's mistakes =====
+==== Common beginner's mistakes ====
+ShellCheck recognizes many common beginner's syntax errors.
 <code bash>
+var = 42                              # Spaces around = in assignments.
+$foo=42                               # $ in assignments.
+for $var in *; do ...                 # $ in for loop variables.
+var$n="Hello"                         # Wrong indirect assignment.
+echo ${var$n}                         # Wrong indirect reference.
+var=(1, 2, 3)                         # Comma separated arrays.
 </code>
-===== Shell bad code =====
+----
+==== Style ====
+ShellCheck can make recommendations to improve style:
+<code bash>
+[[ -z $(find /tmp | grep msg) ]]      # Use grep -q instead.
+a >> log; b >> log; c >> log;         # Use a redirection block instead.
+cat file | grep foo                   # Useless use of cat.
+</code>
 ShellCheck is very easy to install and use. It is built and packaged using Cabal. We can install by apt-get/yum. Or use cabal-install directly like below.
@@ Line 53: / Line 75: @@
 It is recommended to enforce a daily Shell Code Check!