Control.Shell

Simple interface for shell scripting-like tasks.

Documentation

data Shell a

Monad for running shell commands. If a command fails, the entire computation is aborted unless mayFail is used.

Instances

Monad Shell

Functor Shell

Applicative Shell

MonadIO Shell

Guard a b => Guard (Shell a) b

class Guard guard a | guard -> a where

Methods

guard :: String -> guard -> Shell a

Perform a Shell computation; if the computation succeeds but returns a false-ish value, the outer Shell computation fails with the given error message.

Instances

Guard Bool ()

Guard (Maybe a) a

Guard a b => Guard (Shell a) b

shell :: Shell a -> IO (Either String a)

Run a Shell computation. The program's working directory will be restored after executing the computation.

mayFail :: Shell a -> Shell (Either String a)

Perform an action that may fail without aborting the entire computation. Forces serialization.

orElse :: Shell a -> Shell a -> Shell a

Attempt to run the first command. If the first command fails, run the second. Forces serialization of the first command.

withEnv :: String -> (String -> String) -> Shell a -> Shell a

Run a computation with a new value for an environment variable. Note that this will *not* affect external commands spawned using liftIO or which directory is considered the system temp directory.

getEnv :: String -> Shell String

Get the value of an environment variable. Returns the empty string if the variable doesn't exist.

lookupEnv :: String -> Shell (Maybe String)

Get the value of an environment variable. Returns Nothing if the variable doesn't exist.

run :: FilePath -> [String] -> String -> Shell String

Execute an external command. No globbing, escaping or other external shell magic is performed on either the command or arguments. The program's text output will be returned, and not echoed to the screen.

run_ :: FilePath -> [String] -> String -> Shell ()

Like run, but echoes the command's text output to the screen instead of returning it.

runInteractive :: FilePath -> [String] -> Shell ()

Run an interactive process.

genericRun :: FilePath -> [String] -> String -> Shell (Bool, String, String)

Run a program and return a boolean indicating whether the command succeeded, the output from stdout, and the output from stderr. This command will never fail.

sudo :: FilePath -> [String] -> String -> Shell String

Run a command with elevated privileges.

cd :: FilePath -> Shell ()

Change working directory.

cpDir :: FilePath -> FilePath -> Shell ()

Recursively copy a directory. If the target is a directory that already exists, the source directory is copied into that directory using its current name.

pwd :: Shell FilePath

Get the current working directory.

ls :: FilePath -> Shell [FilePath]

List the contents of a directory, sans . and '..'.

mkdir :: Bool -> FilePath -> Shell ()

Create a directory. Optionally create any required missing directories as well.

rmdir :: FilePath -> Shell ()

Recursively remove a directory. Follows symlinks, so be careful.

inDirectory :: FilePath -> Shell a -> Shell a

Execute a command in the given working directory, then restore the previous working directory.

isDirectory :: FilePath -> Shell Bool

Does the given path lead to a directory?

withHomeDirectory :: (FilePath -> Shell a) -> Shell a

Do something with the user's home directory.

inHomeDirectory :: Shell a -> Shell a

Do something *in* the user's home directory.

withAppDirectory :: String -> (FilePath -> Shell a) -> Shell a

Do something with the given application's data directory.

inAppDirectory :: FilePath -> Shell a -> Shell a

Do something *in* the given application's data directory.

forEachFile :: FilePath -> (FilePath -> Shell a) -> Shell [a]

Perform an action on each file in the given directory. This function will traverse any subdirectories of the given as well. File paths are given relative to the given directory; the current working directory is not affected.

cpFiltered :: (FilePath -> Bool) -> FilePath -> FilePath -> Shell ()

Recursively copy a directory, but omit all files that do not match the give predicate.

isFile :: FilePath -> Shell Bool

Does the given path lead to a file?

rm :: FilePath -> Shell ()

Remove a file.

mv :: FilePath -> FilePath -> Shell ()

Rename a file.

cp :: FilePath -> FilePath -> Shell ()

Copy a file. Fails if the source is a directory. If the target is a directory, the source file is copied into that directory using its current name.

file :: File a => FilePath -> a

withTempFile :: String -> (FilePath -> Handle -> Shell a) -> Shell a

Create a temp file in the standard system temp directory, do something with it, then remove it.

withCustomTempFile :: FilePath -> (FilePath -> Handle -> Shell a) -> Shell a

Create a temp file in the standard system temp directory, do something with it, then remove it.

withTempDirectory :: String -> (FilePath -> Shell a) -> Shell a

Create a temp directory in the standard system temp directory, do something with it, then remove it.

withCustomTempDirectory :: FilePath -> (FilePath -> Shell a) -> Shell a

Create a temp directory in given directory, do something with it, then remove it.

inTempDirectory :: Shell a -> Shell a

Performs a command inside a temporary directory. The directory will be cleaned up after the command finishes.

hPutStr :: Handle -> String -> Shell ()

IO.hPutStr lifted into Shell for convenience.

hPutStrLn :: Handle -> String -> Shell ()

IO.hPutStrLn lifted into Shell for convenience.

echo :: String -> Shell ()

putStrLn lifted into Shell for convenience.

(|>) :: Shell String -> (String -> Shell a) -> Shell a

Lazy counterpart to monadic bind. To stream data from a command a to a command b, do 'a |> b'.

module System.FilePath

liftIO :: MonadIO m => forall a. IO a -> m a

Lift a computation from the IO monad.