Documentation

Shell script monad.

Generates a shell script, including hashbang, suitable to be written to a file.

Generates a single line of shell code.

A shell variable.

Expand a shell variable to its value.

A value that is safely quoted.

Quotes the value to allow it to be safely exposed to the shell.

The method used is to replace ' with '"'"' and wrap the value inside single quotes. This works for POSIX shells, as well as other shells like csh.

Adds a shell command to the script.

Variadic argument version of run.

The command can be passed any number of CmdArgs.

Convenient usage of cmd requires the following:

{-# LANGUAGE OverloadedStrings, ExtendedDefaultRules #-}
{-# OPTIONS_GHC -fno-warn-type-defaults #-}
import Control.Monad.Shell
import qualified Data.Text.Lazy as L
default (L.Text)

This allows writing, for example:

demo = script $ do
  cmd "echo" "hello, world"
  name <- newVar "name"
  readVar name
  cmd "echo" "hello" name

The output of a command, or even a more complicated Script can be passed as a parameter to cmd

Examples:

cmd "echo" "hello there," (Output (cmd "whoami"))
cmd "echo" "root's pwent" (Output (cmd "cat" "/etc/passwd" -|- cmd "grep" "root"))

Adds a comment that is embedded in the generated shell script.

Defines a new shell variable.

The name of the variable that appears in the shell script will be based on provided name (which can be mempty), but each call to newVar will generate a new, unique variable name.

Creates a new shell variable, with an initial value.

Gets a Var that refers to a global variable, such as PATH

Defines a shell function, and returns an action that can be run to call the function.

TODO parameter passing to the function

Pipes together two Scripts.

Runs the command, and separates its output into parts (using the IFS)

The action is run for each part, passed a Var containing the part.

As long as the first Script exits nonzero, runs the second script.

if with a monadic conditional

If the conditional exits 0, the first action is run, else the second.

when with a monadic conditional

unless with a monadic conditional

Generates shell code to fill a variable with a line read from stdin.

By default, shell scripts continue running past commands that exit nonzero. Use "stopOnFailure True" to make the script stop on the first such command.

Makes a nonzero exit status be ignored.