What is exec command in bash?
exec command in Linux is used to execute a command from the bash itself. This command does not create a new process it just replaces the bash with the command to be executed. If the exec command is successful, it does not return to the calling process.
How do I redirect errors in Linux?
To redirect stderr as well, you have a few choices:
- Redirect stdout to one file and stderr to another file: command > out 2>error.
- Redirect stdout to a file ( >out ), and then redirect stderr to stdout ( 2>&1 ): command >out 2>&1.
When to use exec or redirection in Bash?
The exec command is often used for redirection. When a file descriptor is redirected with exec it affects the current shell. It will exist for the life of the shell or until it is explicitly stopped. If no command is specified, redirections may be used to affect the current shell environment.
When to use Exec to redirect a file descriptor?
When a file descriptor is redirected with exec it affects the current shell. It will exist for the life of the shell or until it is explicitly stopped. If no command is specified, redirections may be used to affect the current shell environment. Here are some examples of how to use exec for redirection and manipulating file descriptors.
When to use exec or subshell in Bash?
The Basics Whenever we run any command in a Bash shell, a subshell is created by default, and a new child process is spawned (forked) to execute the command. When using exec, however, the command following exec replaces the current shell.
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.