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--- ubuntu:bash:shellcheck [2019/11/29 11:21] – created peter
+++ ubuntu:bash:shellcheck [2019/12/07 01:46] (current) – removed peter
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-====== Ubuntu - Bash - ShellCheck ======
-[[https://github.com/koalaman/shellcheck|ShellCheck]] helps to identify a lot of potential issues in your shell scripts.
-For example, here is one common mistake which ShellCheck picks up.  Most times, the original code will work.  However if we feed $dir with value like "Denny Documents", it hurts.  Sometime the bad code may incur very severe damage!
-# Before:
-<code bash>
-rm -rf $dir
-# After:
-<code bash>
-rm -rf "$dir"
-</code>
-----
-===== More Bad Code Examples =====
-==== 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>
-----
-==== 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.
-<code bash>
-# Install ShellCheck
-sudo apt-get install -y cabal-install
-sudo cabal update
-sudo cabal install shellcheck
-ln -s /root/.cabal/bin/shellcheck /usr/sbin/shellcheck
-# Example: Run check for Shell scripts
-sudo shellcheck my_script.sh
-</code>
-By default, ShellCheck enforces hundreds of rules.  Each rule has a dedicated wiki page, which explains the purpose and improvement suggestion clearly. For example, wiki for Rule SC1000: https://github…shellcheck/wiki/SC1000.  I’m sure you can easily guess the wiki link of other rules.
-Skip some ShellCheck rules, which don’t fit your projects.  For your reference, here are rules I used to skip.
-<code bash>
-# Run test excluding certain rules
-EXCLUDE_CODE_LIST="SC1090,SC1091,SC2154,SC2001,SC2002"
-sudo shellcheck -e $EXCLUDE_CODE_LIST $file
-# Run test against all scripts under a folder
-EXCLUDE_CODE_LIST="SC1090,SC1091,SC2154,SC2001,SC2002"
-find . -name "*.sh" | xargs sudo \
-    shellcheck -e $EXCLUDE_CODE_LIST $file
-</code>
-It is recommended to enforce a daily Shell Code Check!