220-1102 Practice Question: That a script they run daily now fails with…

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  The script's shebang line is incorrect.

  Why it's wrong here

  An incorrect shebang line, such as `#!/bin/bash` being misspelled or pointing to a non-existent interpreter, typically results in an error like "command not found" or "No such file or directory" when the kernel attempts to locate the specified interpreter. It does not usually manifest as a "Permission denied" error for the script itself, assuming the script has execute permissions and the filesystem allows execution. The "Permission denied" error specifically indicates that the *attempt to execute* was blocked, not that the interpreter couldn't be found.

• ✓

  The /usr/local/bin partition is mounted with the noexec option.

  Why this is correct

  When a filesystem is mounted with the `noexec` option, the operating system kernel explicitly prevents the execution of any binaries or scripts located on that partition, regardless of their individual file permissions. Even if a script has the execute bit set (e.g., `chmod +x script.sh`), attempting to run it from a `noexec`-mounted filesystem will result in a "Permission denied" error. This security feature is designed to prevent the execution of potentially malicious code from certain partitions.

• ✗

  The user does not have read permission on the script.

  Why it's wrong here

  If the user lacked read permission on the script, the shell would be unable to open and interpret its contents. This would typically lead to a "Permission denied" error, but it would be due to the inability to *read* the file's data, not specifically an inability to *execute* it as a program. Given that the script is attempting to be run daily, and assuming standard permissions like `r-x` for others, read access is likely present, making this an unlikely cause for an execution failure.

• ✗

  The script has been replaced with a directory.

  Why it's wrong here

  Attempting to execute a directory instead of a script or executable file will result in a distinct error message, typically "Is a directory" or "Permission denied" followed by "Is a directory" on some systems. This error clearly indicates that the target is a directory, not an executable file. A generic "Permission denied" error without this specific clarification suggests that the file itself is recognized as an executable type, but its execution is being blocked by a different mechanism.

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