Display or set shell attributes and variables.
The set command is primarily used to display existing shell variables and set their values. When using set to modify shell attributes, the "+" and "-" signs are used to enable and disable specific modes, respectively. The set command cannot define new shell variables; use the declare command in the format variable_name=value to define new variables.
set [options] [parameters]
-a: Mark modified or created variables for export to the environment.
-b: Cause the status of terminated background jobs to be reported immediately.
-C: Prevent existing regular files from being overwritten by redirection.
-d: Shell uses a hash table to remember the locations of commands to speed up execution. Use -d to disable this.
-e: Exit immediately if a command exits with a non-zero status.
-f: Disable pathname expansion (globbing).
-h: Remember the location of functions as they are defined.
-H: Enable "!" style history substitution.
-k: All arguments in the form of assignment statements are placed in the environment for a command.
-l: Save and restore the binding of a name in a for loop.
-m: Enable job control (monitor mode).
-n: Read commands but do not execute them.
-p: Turn on privileged mode.
-P: If set, do not follow symbolic links when performing commands such as cd.
-t: Exit after reading and executing one command.
-u: Treat unset variables as an error when performing parameter expansion.
-v: Print shell input lines as they are read.
-x: Print commands and their arguments as they are executed.
Used to disable a previously set attribute.
Use the declare command to define a new environment variable "mylove" and set its value to "Visual C++":
declare mylove='Visual C++' # Define a new environment variable
Use the set command to export the newly defined variable to the environment:
set -a mylove # Set as an environment variable
After executing this command, the corresponding environment variable will be added. You can use the env and grep commands to display and search for the environment variable "mylove":
env | grep mylove # Display the value of the environment variable
At this point, the command will output the value of the environment variable.