File descriptor 1 is the standard output (stdout). File descriptor 2 is the standard error (stderr). At first, 2>1 may look like a good way to redirect stderr to stdout. However, it will actually be interpreted as “redirect stderr to a file named 1“. & indicates that what follows and precedes is a file descriptor, … Read more
Use printf instead: printf “hello\nworld\n” printf behaves more consistently across different environments than echo.
foo=”Hello” foo=”${foo} World” echo “${foo}” > Hello World In general to concatenate two variables you can just write them one after another: a=”Hello” b=’World’ c=”${a} ${b}” echo “${c}” > Hello World
The test command (written as [ here) has a “not” logical operator, ! (exclamation mark): if [ ! -f /tmp/foo.txt ]; then echo “File not found!” fi