SC2307 – ShellCheck Wiki

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'expr' expects 3+ arguments but sees 1. Make sure each operator/operand is a separate argument, and escape <>&|.

Problematic code:

# | not escaped
expr 1 | 2
# > not escaped
expr "$foo" >= "$bar"

# Missing spaces around +
expr 1+2
# Unexpected quoting around an expression
expr "1 + 2"

Correct code:

expr 16 \| 7
expr "$foo" \>= "$bar"
expr 1 + 2


ShellCheck found an expr command with 1 or 2 arguments. expr normally expects 3 or more.

Generally, this happens for one of two reasons:

Make sure each operator or operand to expr is a separate argument, and that anything containing shell metacharacters is escaped. The correct code shows examples of each.



ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.