if true do nothing else do

How do I write the "do nothing" statement in the following example?

Example:

if (( "$x"="1" && "$y"="a" && "$z"="happy" ))
then
do nothing
else
command
command
fi

if (( "$x"="1" && "$y"="a" && "$z"="happy" )); then
     :
else
   command
   command
fi

Another way, invert your test :

Code:

if (( "$x"!="1" || "$y"!="a" || "$z"!="happy" ))
then
   command
   command
fi

========================

value=$( grep -ic "benjamin" /etc/passwd )
if [ $value -eq 1 ]
then
  echo "I found Benjamin"
fi

value=$( grep -ic "benjamin" /etc/passwd )
if [ $value -ge 1 ]
then

  if [ $value -eq 1 ]
  then
    echo "I found Benjamin"
  elif [ $value -eq 2 ]
  then
    echo "I found two Benjamins"
  else
    echo "There are too many Benjamins"
  fi

fi

if [ -n $value ] 
then
  echo "variable value has a value or $value"
fi

The -n operator is for checking if a variable has a string value or not.

The -z operator is the opposite of -n

if [[ -n $1 ]] && [[ -r $1 ]]
then
  echo "File exists and is readable"
fi

if [[ -z $1 ]] || [[ ! -r $1 ]]
then
  echo "Either you didn't give me a value or file is unreadable"
  exit 2
fi