Unixkomento

Unixkomento refers to the instruction issued to a Unix-like operating system's shell to perform an action. In Finnish computing, Unixkomento is the term used for a Unix command. A Unixkomento generally follows the pattern: command name, optional options, and arguments. Commands can be built into the shell or external programs.

Built-in commands are provided by the shell itself (for example, changing directories or exiting a session). External commands are separate executable files found in the filesystem, usually located through the PATH environment variable.

Syntax and conventions: Most commands accept short options beginning with a single dash (for example, -l) and, in some cases, long options beginning with two dashes (for example, --version). Options may take arguments; some commands require no options.

Input, output, and chaining: Unixkomento outputs can be redirected using >, >>, or a pipe symbol | to feed the output of one command into another. Redirection and pipes enable powerful data processing pipelines.

Environment and scripting: The shell provides variables and a command history; scripts written in shell languages begin with a shebang (for example #!/bin/sh) and must have execute permission. They automate sequences of Unixkomento.

Standardization: POSIX and the Single UNIX Specification define a common baseline for behavior and interfaces of many commands, aiding portability across Unix-like systems.

Common examples: ls, cd, pwd, cat, echo, grep, find, awk, sed, man.

See also: Unix, POSIX, shell, command line.