Fli
Execute CLI commands from your F# code in F# style!
Fli is part of the F# Advent Calendar 2022: A little story about Fli
Features
- Starting processes easily
- Execute CLI commands in your favourite shell
- F# computation expression syntax
- Wrap authenticated CLI tools
- No external dependencies
Install
Get it from Nuget: dotnet add package Fli
Usage
open Fli and start
For example:
cli {
Shell CMD
Command "echo Hello World!"
}
|> Command.executethat starts CMD.exe as Shell and echo Hello World! is the command to execute.
Run a file with PowerShell from a specific directory:
cli {
Shell PWSH
Command "test.bat"
WorkingDirectory (Environment.GetFolderPath Environment.SpecialFolder.UserProfile)
}
|> Command.executeExecuting programs with arguments:
cli {
Exec "path/to/executable"
Arguments "--info"
}
|> Command.executean example with git:
cli {
Exec "git"
Arguments ["commit"; "-m"; "Fixing issue #1337."]
}
|> Command.executeAdd a verb to your executing program:
cli {
Exec "adobe.exe"
Arguments (Path.Combine ((Environment.GetFolderPath Environment.SpecialFolder.UserProfile), "test.pdf"))
Verb "open"
}
|> Command.executeWrite output to a specific file:
cli {
Exec "dotnet"
Arguments "--list-sdks"
Output @"absolute\path\to\dotnet-sdks.txt"
}
|> Command.executeWrite output to a function (logging, printing, etc.):
let log (output: string) = Debug.Log($"CLI log: {output}")
cli {
Exec "dotnet"
Arguments "--list-sdks"
Output log
}
|> Command.executeAdd environment variables for the executing program:
cli {
Exec "git"
EnvironmentVariables [("GIT_AUTHOR_NAME", "Jon Doe"); ("GIT_AUTHOR_EMAIL", "[email protected]")]
}
|> Command.executeAdd credentials to program:
cli {
Exec "program"
Credentials ("domain", "bobk", "password123")
}
|> Command.executeHint: Running a process as a different user is supported on all platforms. Other options (Domain, Password) are only available on Windows. As an alternative for not Windows based systems there is:
cli {
Exec "path/to/program"
Username "admin"
}
|> Command.executeCommand.execute
Command.execute returns record: type Output = { Id: int; Text: string option; ExitCode: int; Error: string option }
which has getter methods to get only one value:
toId: Output -> int
toText: Output -> string
toExitCode: Output -> int
toError: Output -> stringexample:
cli {
Shell CMD
Command "echo Hello World!"
}
|> Command.execute // { Id = 123; Text = Some "Hello World!"; ExitCode = 0; Error = None }
|> Output.toText // "Hello World!"
// same with Output.toId:
cli { ... }
|> Command.execute // { Id = 123; Text = Some "Hello World!"; ExitCode = 0; Error = None }
|> Output.toId // 123
// same with Output.toExitCode:
cli { ... }
|> Command.execute // { Id = 123; Text = Some "Hello World!"; ExitCode = 0; Error = None }
|> Output.toExitCode // 0
// in case of an error:
cli { ... }
|> Command.execute // { Id = 123; Text = None; ExitCode = 1; Error = Some "This is an error!" }
|> Output.toError // "This is an error!"Printing Output fields
There are printing methods in Output too:
printId: Output -> unit
printText: Output -> unit
printExitCode: Output -> unit
printError: Output -> unitInstead of writing:
cli { ... }
|> Command.execute
|> Output.toText
|> printfn "%s"For a little shorter code you can use:
cli { ... }
|> Command.execute
|> Output.printTextCommand.toString
Command.toString concatenates only the the executing shell/program + the given commands/arguments:
cli {
Shell PS
Command "Write-Host Hello World!"
}
|> Command.toString // "powershell.exe -Command Write-Host Hello World!"and:
cli {
Exec "cmd.exe"
Arguments [ "/C"; "echo"; "Hello World!" ]
}
|> Command.toString // "cmd.exe /C echo Hello World!"Builder operations:
ShellContext operations (cli { Shell ... }):
| Operation | Type |
|---|---|
Shell |
Fli.Shells |
Command |
string |
Input |
string |
Output |
Outputs (see below) |
WorkingDirectory |
string |
EnvironmentVariable |
string * string |
EnvironmentVariables |
(string * string) list |
Encoding |
System.Text.Encoding |
CancelAfter |
int |
ExecContext operations (cli { Exec ... }):
| Operation | Type |
|---|---|
Exec |
string |
Arguments |
string / string seq / string list / string array |
Input |
string |
Output |
Outputs (see below) |
Verb |
string |
Username |
string |
Credentials |
string * string * string |
WorkingDirectory |
string |
EnvironmentVariable |
string * string |
EnvironmentVariables |
(string * string) list |
Encoding |
System.Text.Encoding |
CancelAfter |
int |
Currently provided Fli.Shells:
CMDrunscmd.exe /c ...orcmd.exe /k ...(depends ifInputis provided or not)PSrunspowershell.exe -Command ...PWSHrunspwsh.exe -Command ...WSLrunswsl.exe -- ...BASHrunsbash -c ...CUSTOM (shell: string * flag: string)runs the specifiedshellwith the specified starting argument (flag)
Provided Fli.Outputs:
File of stringa string with an absolute path of the output file.StringBuilder of StringBuildera StringBuilder which will be filled with the output text.Custom of Func<string, unit>a custom function (string -> unit) that will be called with the output string (logging, printing etc.).
Do you miss something?
Open an issue or start a discussion.
Inspiration
Use CE's for CLI commands came in mind while using FsHttp.