![]() ![]() Sometimes you want to give a command an argument that contains characters special to fish, like spaces or $ or *. A switch almost always begins with one or two hyphens. Switch or Option: A special kind of argument that alters the behavior of a command. Redirection: An operation that changes one of the input or output streams associated with a job. Pipeline: A set of commands strung together so that the output of one command is the input of the next command. By using functions, it is possible to string together multiple simple commands into one more advanced command. In echo foo the “echo” is a builtin command, in command echo foo the “echo” is an external command, provided by a file like /bin/echo.įunction: A block of commands that can be called as if they were a single command. External commands are provided on your system, as executable files. In echo foo, the “echo” is a builtin.Ĭommand: A program that the shell can run, or more specifically an external program that the shell runs in another process. Builtins are so closely tied to the operation of the shell that it is impossible to implement them as external commands. In echo foo, the “foo” is an argument.īuiltin: A command that is implemented by the shell. Here we define some of the terms used on this page and throughout the rest of the fish documentation:Īrgument: A parameter given to a command. ![]() So the basic idea of fish is the same as with other unix shells: It gets a commandline, runs expansions, and the result is then run as a command. Try man your-command-here to get information on your command’s switches. For example, -help will usually display a help text, -version will usually display the command version, and -i will often turn on interactive prompting before taking action. There are some switches, however, that are common to most commands. Switches differ between commands and are usually documented on a command’s manual page. ![]() By using the -l switch, the behavior of ls is changed to not only display the filename, but also the size, permissions, owner, and modification time of each file. For example, the ls command usually lists the names of all files and directories in the current working directory. Switches almost always start with one or more hyphens - and alter the way a command operates. Multiple commands can be written on the same line by separating them with semicolons.Ī switch is a very common special type of argument. Every command ends with either a newline (by pressing the return key) or a semicolon. Open: Open files with the default application associated with each filetypeĬommands and arguments are separated by the space character ' '. Man: Display a manual page - try man ls to get help on your “ls” command, or man mv to get information about “mv”. Otherwise the whole filename, including the directory (like /home/me/code/checkers/checkers or. If the program file is located in one of the PATH directories, you can just type the name of the program to use it. All of these commands follow the same basic syntax.Įvery program on your computer can be used as a command in fish. There are commands for repeating other commands, commands for assigning variables, commands for treating a group of commands as a single command, etc. In this example the output is hello world.Įverything in fish is done with commands. Using abbr means other developers can understand your terminal history.Įasy to use a shortcut that’s close to what you want and edit it.Echo command writes its arguments to the screen. The abbr expands “live”, the git completions work as normal and commandline doesn’t have to lie or do any other hacks like that.Ĭlean history. I converted this from an alias that I used on a daily basis for elixir development, here are the advantages so far: Let’s look at the following example: abbr -add miex "iex -erl "-kernel shell_history enabled" -S mix" Makes copy-pasting a command-line for instructions to others, difficult of not impossibleĬommand history will be recorded as the alias, so history loses valueĪliases become less valuable if you have to edit the optionsĪbbreviations work on the same principle as aliases but with the main advantage that an abbreviation will get expanded ‘live’ as is being typed. They hide what is really happening as they are resolved behind the scenes The way aliases work on most shells the following drawbacks become apparent: The main issue is that aliases are expanded behind the scenes, take the following alias: alias rm='rm -Rfi' Aliases allow you to define new commands by substituting a string for the first token of a simple command. I recently came across one of Fish shell best and likely most underrated features, abbreviations a great alternative to aliases and dare I say a full replacement.Īn alias is a (usually short) name that the shell translates into another (usually longer) name or command. ![]()
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