Bash Script multi conditional fails

Question

In this Bash Shell script I like to check if the length of the string is zero. In that case the script should echo an error message and exit.

dbname="ssss"
dbuser=""

if [ -z "$dbname"]
then
        echo "DB name is not specified!"
        exit
fi

if [ -z "$dbuser"]
then
        echo "DB user is not specified!"
        exit
fi

If dbname is "" it works as expected. But if it has some value and I was expecting to see it exit at the next conditional, I get this error message:

Script.sh: line 4: [: missing `]'
DB user is not specified!

Why the error message?

You are working too hard. Try ${dbname:?DB name is not specified} — William Pursell
– William Pursell, Commented Dec 27, 2011 at 21:29

Fred Foo · Accepted Answer · 2011-12-27 20:43:17Z

5

[ -z "$dbuser"]

should be

[ -z "$dbuser" ]
# note: ------^

answered Dec 27, 2011 at 20:43

Fred Foo

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Comments

Donald Miner · Accepted Answer · 2011-12-27 20:46:46Z

1

You are missing a space after the quotes.

if [ -z "$dbuser"]

If $dbuser is empty, it looks like this to bash, which is valid because it has a space:

if [ -z ]

When $dbuser is populated, the ] will be attached to the string, and will think the ] is part of the string:

if [ -z theuser]

To fix this, just add a space after your second double quote:

if [ -z "$dbuser" ]

Now, it'll get translated as the following, and everything is fine:

if [ -z theuser ]

answered Dec 27, 2011 at 20:46

Donald Miner

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