bash: [: missing `]'

[: missing ]'means bash ran the[command and none of its arguments was a lone]. In bash, [is not punctuation: it is a command, a synonym oftest, and its **last argument must be ]**. If the bracket is attached to another word, or never typed, [complains and returns an error status, theiftreats the condition as false and the script quietly takes theelse` path.

Reproduce the error

The then keyword follows the semicolon, but the test was never closed:

x=abc
if [ "$x" = abc; then
  echo "match"
fi
echo "after the if"

bash: line 2: [: missing `]'
after the if

The message names the line of the test. Interactive shells omit line N: and print bash: [: missing ]'`. Note that the script continues: the failed test is only a false condition.

Why it happens

[ "$x" = abc ] is parsed like any command line: the words are [, "$x", =, abc and ]. Bash needs the final word to be exactly ]. Three typical mistakes break that rule:

1. No space before the bracket. [ "$x" = abc] passes the single word abc], so the last argument is not ].
2. The bracket is missing. This happens when a condition is edited or a [[ ... ]] line is cut halfway.
3. A separator sits in the wrong place. ; ends a command, so everything after it belongs to the next command, and the [ before it stays unclosed.

The same rule explains why [ -f "$file" ] needs spaces just inside the brackets, and why [ $x = abc ] with an empty x produces a different error, unary operator expected or too many arguments.

Fix it

Close the test with a standalone ] before the semicolon:

x=abc
if [ "$x" = abc ]; then
  echo "match"
fi

match

For bash scripts the [[ ]] form is safer, because the shell parses it as syntax and does not word-split variables:

x=abc
if [[ $x == abc ]]; then
  echo "match"
fi

match

Confirm the fix by running the script again: the error line disappears and the branch you expect runs.

Check scripts before running them

bash -n script.sh parses the file without running it, and it does not report this error, because a missing ] is a runtime error of the [ command, not a syntax error. A linter such as shellcheck is the usual way to catch missing spaces around brackets before the script runs. Quote variables inside [ ] as a habit: it avoids the neighbouring errors with empty values and spaces.

Related errors

• too many arguments appears when an unquoted variable expands to several words.
• integer expression expected appears when -eq, -lt or similar compare a non-number.
• The file existence page shows correct [ -f ] and [ -d ] tests.

FAQ