Instead of             use

 tmpfile=/tmp/me$$      tmpfile=`mktemp`

 [ ]                     [[ ]]

(( ++count ))
(( $# )) || { echo "Expected an argument to the script." >&2; exit 1; }

read filesize _ < <(wc -c myfile)
openssl base64 <<< "Bar!" # as opposed to the more expensive: echo "Bar!" | openssl base64
content=$(<file) # as opposed to the more expensive: content=$(cat file)

rm "$(grep -l foo <<< "$(</my/file.list)")"

files=(/foo/*); for file in "${files[@]}"; do pinch "$file"; done

tmpfile=`mktemp`

tmpfile=$(mktemp)

foo="$( some
          multiline
          command  in a string)"

foo="$( some
          multiline
          command  in a string)"

[[ "$str" = @(+([a-z])?([0-9])) ]]