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When to use the redirection operator in Bash?
The redirection operator [ n ]<& word is used to duplicate input file descriptors. If word expands to one or more digits, the file descriptor denoted by n is made to be a copy of that file descriptor.
How does input redirection work in Linux and Unix?
Summary. Each file in Linux has a corresponding File Descriptor associated with it. The keyboard is the standard input device while your screen is the standard output device. “>” is the output redirection operator. “>>” appends output to an existing file. “<” is the input redirection operator. “>&”re-directs output of one file to another.
When to use file descriptor 2 in Bash?
File descriptor 2 is duplicated. If host is a valid hostname or Internet address, and port is an integer port number or service name, Bash attempts to open the corresponding TCP socket. If host is a valid hostname or Internet address, and port is an integer port number or service name, Bash attempts to open the corresponding UDP socket.
How to assign a file descriptor to a redirection?
Each redirection that may be preceded by a file descriptor number may instead be preceded by a word of the form { varname }. In this case, for each redirection operator except >&- and <&-, the shell will allocate a file descriptor greater than 10 and assign it to { varname }.
How does a redirection work in a shell?
This type of redirection instructs the shell to read input from the current source until a line containing only word (with no trailing blanks) is seen. All of the lines read up to that point are then used as the standard input (or file descriptor n if n is specified) for a command.
Where can I find keyword Bash redirection?
You should google with keyword bash redirection for some detailed information. Here is a nice article for reference. For your question, the crontab will run 45627.sh1 scripts at 00:01 everyday and append its error and output to the cron.log file. Not the answer you’re looking for?
What causes a redirection to fail in Bash?
If host is a valid hostname or Internet address, and port is an integer port number or service name, Bash attempts to open the corresponding UDP socket. A failure to open or create a file causes the redirection to fail.