FILE -ef FILE (conditional operator)

true if file1 is a hard link to file2, i.e. if it refers to the same device and inode numbers.

-ef is not included in POSIX. Avoid it if you want to stay compatible with POSIX shells.

Links

• Bash manual
• Advanced Bash-Scripting Guide
• POSIX specification of test

Examples

Different ways to test if a file is a hard link to another file:

1 2 3 4

test ~/file1.txt -ef ~/file2.txt && echo "hard link" [ ~/file1.txt -ef ~/file2.txt ] && echo "hard link" # Bash [[ ~/file1.txt -ef ~/file2.txt ]] && echo "hard link"