Portability | portable |
---|---|
Stability | provisional |
Maintainer | John Goerzen <jgoerzen@complete.org> |
Copyright (c) 2006-2009 John Goerzen, jgoerzen@complete.org
This module provides shell-like commands. Most, but not all, are designed to be used directly as part of a HSH pipeline. All may be used outside HSH entirely as well.
- abspath :: FilePath -> IO FilePath
- appendTo :: FilePath -> String -> IO String
- basename :: FilePath -> FilePath
- bracketCD :: FilePath -> IO a -> IO a
- catFrom :: [FilePath] -> Channel -> IO Channel
- catBytes :: Int -> Maybe Integer -> Handle -> Handle -> IO ()
- catBytesFrom :: Int -> Handle -> Maybe Integer -> Handle -> Handle -> IO ()
- catTo :: FilePath -> Channel -> IO Channel
- catToFIFO :: FilePath -> Channel -> IO Channel
- cd :: FilePath -> IO ()
- cut :: Integer -> Char -> String -> String
- cutR :: [Integer] -> Char -> String -> String
- dirname :: FilePath -> FilePath
- discard :: Handle -> Handle -> IO ()
- echo :: Channelizable a => a -> Channel -> IO Channel
- exit :: Int -> IO a
- glob :: FilePath -> IO [FilePath]
- grep :: String -> [String] -> [String]
- grepV :: String -> [String] -> [String]
- egrep :: String -> [String] -> [String]
- egrepV :: String -> [String] -> [String]
- joinLines :: [String] -> [String]
- lower :: String -> String
- upper :: String -> String
- mkdir :: FilePath -> FileMode -> IO ()
- numberLines :: [String] -> [String]
- pwd :: IO FilePath
- readlink :: FilePath -> IO FilePath
- readlinkabs :: FilePath -> IO FilePath
- rev :: [String] -> [String]
- revW :: [String] -> [String]
- setenv :: ShellCommand cmd => [(String, String)] -> cmd -> EnvironCommand cmd
- space :: [String] -> [String]
- unspace :: [String] -> [String]
- tac :: [String] -> [String]
- tee :: [FilePath] -> ByteString -> IO ByteString
- teeFIFO :: [FilePath] -> ByteString -> IO ByteString
- tr :: Char -> Char -> String -> String
- trd :: Char -> String -> String
- wcW :: [String] -> [String]
- wcL :: [String] -> [String]
- unsetenv :: ShellCommand cmd => [String] -> cmd -> EnvironCommand cmd
- uniq :: String -> String
Documentation
abspath :: FilePath -> IO FilePathSource
Return the absolute path of the arg. Raises an error if the computation is impossible.
bracketCD :: FilePath -> IO a -> IO aSource
Changes the current working directory to the given path, executes the given I/O action, then changes back to the original directory, even if the I/O action raised an exception.
This is an alias for the MissingH function System.Path.bracketCWD.
catFrom :: [FilePath] -> Channel -> IO ChannelSource
Load the specified files and display them, one at a time.
The special file -
means to display the input. If it is not given,
no input is processed (though a small amount may be read into a buffer).
Unlike the shell cat, -
may be given twice. However, if it is, you
will be forcing Haskell to buffer the input.
Note: buffering behavior here is untested.
See also catFromBS
, catBytes
.
:: Int | Preferred chunk size; data will be read in chunks of this size |
-> Maybe Integer | Maximum amount of data to transfer |
-> Handle | Handle for input |
-> Handle | Handle for output |
-> IO () |
Copy data in chunks from stdin to stdout, optionally with a fixed
maximum size. Uses strict ByteStrings internally. Uses hSetBuffering
to set the buffering of the input handle to blockbuffering in chunksize
increments as well, but restores original buffering before returning.
See also catFrom
, catBytesFrom
:: Int | Preferred chunk size; data will be read in chunks of this size |
-> Handle | Handle to read from |
-> Maybe Integer | Maximum amount of data to transfer |
-> Handle | Handle for input (ignored) |
-> Handle | Handle for output |
-> IO () |
Generic version of catBytes
; reads data from specified Handle, and
ignores stdin.
catTo :: FilePath -> Channel -> IO ChannelSource
Takes input, writes it to the specified file, and does not pass it on.
The return value is the empty string. See also catToBS
,
catToFIFO
catToFIFO :: FilePath -> Channel -> IO ChannelSource
Like catTo
, but opens the destination in ReadWriteMode instead of
ReadOnlyMode. Due to an oddity of the Haskell IO system, this is required
when writing to a named pipe (FIFO) even if you will never read from it.
This call will BLOCK all threads on open until a reader connects.
This is provided in addition to catTo
because you may want to cat to
something that you do not have permission to read from.
This function is only available on POSIX platforms.
See also catTo
An alias for System.Directory.setCurrentDirectory.
Want to change to a user's home directory? Try this:
glob "~jgoerzen" >>= cd . head
See also bracketCD
.
cut :: Integer -> Char -> String -> StringSource
Split a list by a given character and select the nth list.
cut ' ' 2 "foo bar baz quux" -> "bar"
cutR :: [Integer] -> Char -> String -> StringSource
Split a list by a given character and select ranges of the resultant lists.
cutR [2..4] ' ' "foo bar baz quux foobar" -> "baz quux foobar" cutR [1..1000] ' ' "foo bar baz quux foobar" -> "bar baz quux foobar" cutR [-1000..1000] ' ' "foo bar baz quux foobar" -> "foo bar baz quux foobar"
Note that too large and too small indices are essentially ignored.
discard :: Handle -> Handle -> IO ()Source
Read all input and produce no output. Discards input completely.
echo :: Channelizable a => a -> Channel -> IO ChannelSource
Takes a string and sends it on as standard output.
The input to this function is never read.
You can pass this thing a String, a ByteString, or even a Handle.
See also echoBS
.
glob :: FilePath -> IO [FilePath]Source
Takes a pattern. Returns a list of names that match that pattern. Handles:
~username at beginning of file to expand to user's home dir ? matches exactly one character * matches zero or more characters [list] matches any character in list [!list] matches any character not in list
The result of a tilde expansion on a nonexistant username is to do no tilde expansion.
The tilde with no username equates to the current user.
Non-tilde expansion is done by the MissingH module System.Path.Glob.
grep :: String -> [String] -> [String]Source
Search for the string in the lines. Return those that match. Same as:
grep needle = filter (isInfixOf needle)
grepV :: String -> [String] -> [String]Source
Search for the string in the lines. Return those that do NOT match.
egrep :: String -> [String] -> [String]Source
Search for the regexp in the lines. Return those that match.
egrepV :: String -> [String] -> [String]Source
Search for the regexp in the lines. Return those that do NOT match.
upper :: String -> StringSource
Inverse of double space; drop empty lines
Convert a string to all upper or lower case
mkdir :: FilePath -> FileMode -> IO ()Source
Creates the given directory. A value of 0o755 for mode would be typical.
An alias for System.Posix.Directory.createDirectory.
The second argument will be ignored on non-POSIX systems.
numberLines :: [String] -> [String]Source
Number each line of a file
readlink :: FilePath -> IO FilePathSource
Return the destination that the given symlink points to.
An alias for System.Posix.Files.readSymbolicLink
This function is only available on POSIX platforms.
readlinkabs :: FilePath -> IO FilePathSource
As readlink
, but turns the result into an absolute path.
This function is only available on POSIX platforms.
setenv :: ShellCommand cmd => [(String, String)] -> cmd -> EnvironCommand cmdSource
Sets an environment variable, replacing an existing one if it exists.
Here's a sample ghci session to illustrate. First, let's see the defaults for some variables:
Prelude HSH> runIO $ "echo $TERM, $LANG" xterm, en_US.UTF-8
Now, let's set one:
Prelude HSH> runIO $ setenv [("TERM", "foo")] $ "echo $TERM, $LANG" foo, en_US.UTF-8
Or two:
Prelude HSH> runIO $ setenv [("TERM", "foo")] $ setenv [("LANG", "de_DE.UTF-8")] $ "echo $TERM, $LANG" foo, de_DE.UTF-8
We could also do it easier, like this:
Prelude HSH> runIO $ setenv [("TERM", "foo"), ("LANG", "de_DE.UTF-8")] $ "echo $TERM, $LANG" foo, de_DE.UTF-8
It can be combined with unsetenv:
Prelude HSH> runIO $ setenv [("TERM", "foo")] $ unsetenv ["LANG"] $ "echo $TERM, $LANG" foo,
And used with pipes:
Prelude HSH> runIO $ setenv [("TERM", "foo")] $ "echo $TERM, $LANG" -|- "tr a-z A-Z" FOO, EN_US.UTF-8
See also unsetenv
.
tac :: [String] -> [String]Source
Reverse words on each line
Reverse lines in a String (like Unix tac).
Implemented as:
tac = reverse
See uniq
.
tee :: [FilePath] -> ByteString -> IO ByteStringSource
Takes input, writes it to all the specified files, and passes it on. This function does /NOT' buffer input.
See also catFrom
.
teeFIFO :: [FilePath] -> ByteString -> IO ByteStringSource
FIFO-safe version of teeBS
.
This call will BLOCK all threads on open until a reader connects.
This function is only available on POSIX platforms.
tr :: Char -> Char -> String -> StringSource
Translate a character x to y, like:
tr 'e' 'f'
Or, in sed,
y//
unsetenv :: ShellCommand cmd => [String] -> cmd -> EnvironCommand cmdSource
Removes an environment variable if it exists; does nothing otherwise.
See also setenv
, which has a more extensive example.