echo $123 outputs 23

[adit]

I didn't define any environment variable 123. When I type echo $123 in the terminal I get the output 23. How?

[GeneralZod]

I didn't define any environment variable 123. When I type echo $123 in the terminal I get the output 23. How?

Presumably, "$123" is parsed as


$1 followed by the string


23

[surfer]

#!/bin/bash
echo $123


if you save that in a shell script and call is test.sh



$ ./test.sh hello

will give you hello23.

bash variables must not start with numbers! $1 is the first argument you pass on the command line.