#!/bin/sh ## Example: a typical script with several problems for f in $(ls *.m3u) do grep -qi hq.*mp3 $f \ && echo -e 'Playlist $f contains a HQ file in mp3 format' done

#!/bin/sh ## Example: The shebang says 'sh' so shellcheck warns about portability ## Change it to '#!/bin/bash' to allow bashisms for n in {1..$RANDOM} do str="" if (( n % 3 == 0 )) then str="fizz" fi if [ $[n%5] == 0 ] then str="$strbuzz" fi if [[ ! $str ]] then str="$n" fi echo "$str" done

#!/bin/bash ## Example: ShellCheck can detect some higher level semantic problems while getopts "nf:" param do case "$param" in f) file="$OPTARG" ;; v) set -x ;; esac done case "$file" in *.gz) gzip -d "$file" ;; *.zip) unzip "$file" ;; *.tar.gz) tar xzf "$file" ;; *) echo "Unknown filetype" ;; esac if [[ "$$(uname)" == "Linux" ]] then echo "Using Linux" fi

#!/bin/bash ## Example: ShellCheck can detect many different kinds of quoting issues if ! grep -q backup=true.* "~/.myconfig" then echo 'Backup not enabled in $HOME/.myconfig, exiting' exit 1 fi if [[ $1 =~ "-v(erbose)?" ]] then verbose='-printf "Copying %f\n"' fi find backups/ \ -iname *.tar.gz \ $verbose \ -exec scp {} “myhost:backups” +

#!/bin/bash
var="$1"

if [ -n $var ]
then
  echo " -n says Not Empty"
else
  echo " -n says Empty"
fi

if [ -z $var ]
then
  echo " -z says Empty"
else
  echo " -z says Not Empty"
fi