The article discusses two unexpected sources of code execution in bash: arithmetic expressions and the test -v command, which can evaluate arbitrary code under certain conditions.
```
if [ "${num}" -eq 42 » ]
```
```
$ [ -v 'x[$(cat /etc/passwd > /tmp/pwned) » ' ]]
```
```
if [ "${num}" -eq 42 » ]
```
```
$ [ -v 'x[$(cat /etc/passwd > /tmp/pwned) » ' ]]
```
