-t FD (conditional operator)

true if FD is a file descriptor, which is opened on a terminal.

Links

• Bash manual
• POSIX specification of test

Examples

Different ways to test if a file descriptor is opened on a terminal:

1 2 3 4

test -t 1 && echo "stdout opened on terminal" [ -t 1 ] && echo "stdout opened on terminal" # Bash [[ -t 1 ]] && echo "stdout opened on terminal"