Shell script variable not empty (-z option)

Shell Problem Overview

How to make sure a variable is not empty with the -z option ?

errorstatus="notnull"
if [ !-z $errorstatus ]
then
   echo "string is not null"
fi

It returns the error :

./test: line 2: [: !-z: unary operator expected

Of course it does. After replacing the variable, it reads [ !-z ], which is not a valid [ command. Use double quotes, or [[.

if [ ! -z "$errorstatus" ]

if [[ ! -z $errorstatus ]]

Why would you use -z? To test if a string is non-empty, you typically use -n:

if test -n "$errorstatus"; then
echo errorstatus is not empty
fi

I think this is the syntax you are looking for:

if [ -z != $errorstatus ] 
then
commands
else
commands
fi

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Content Type	Original Author	Original Content on Stackoverflow
Question	Sreeraj	View Question on Stackoverflow
Solution 1 - Shell	Ignacio Vazquez-Abrams	View Answer on Stackoverflow
Solution 2 - Shell	William Pursell	View Answer on Stackoverflow
Solution 3 - Shell	vinod garag	View Answer on Stackoverflow

Content Type

Original Author

Original Content on Stackoverflow

Question

Solution 1 - Shell

Solution 2 - Shell