File descriptor - An integer that identifies an open file within a process. This number is obtained as a result of opening a file. Operations which read, write, or close a file would take the file descriptor as an input parameter. In many operating system implementations, file descriptors are small integers which index a table of open files. In …

Shell - File Descriptor.sh

# 0, Standard input (stdin) <0
# 1, Standard output (stdout) 1>
# 2, Standard error (stderr) 2>
# Examples:

# redirect stderr (2) to stdout (1)
2>&1