HSH-1.2.6: Library to mix shell scripting with Haskell programsSource codeContentsIndex
HSH.ShellEquivs
Portabilityportable
Stabilityprovisional
MaintainerJohn Goerzen <jgoerzen@complete.org>
Description

Copyright (c) 2006-2008 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.

Synopsis
abspath :: FilePath -> IO FilePath
appendTo :: FilePath -> String -> IO String
basename :: FilePath -> FilePath
bracketCD :: FilePath -> IO a -> IO a
catFrom :: [FilePath] -> String -> IO String
catFromBS :: [FilePath] -> ByteString -> IO ByteString
catTo :: FilePath -> String -> IO String
catToBS :: FilePath -> ByteString -> IO ByteString
cd :: FilePath -> IO ()
cut :: Integer -> Char -> String -> String
cutR :: [Integer] -> Char -> String -> String
dirname :: FilePath -> FilePath
echo :: String -> String -> String
echoBS :: ByteString -> ByteString -> ByteString
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]
space :: [String] -> [String]
unspace :: [String] -> [String]
tac :: [String] -> [String]
tee :: [FilePath] -> String -> IO String
teeBS :: [FilePath] -> ByteString -> IO ByteString
tr :: Char -> Char -> String -> String
trd :: Char -> String -> String
wcW :: [String] -> [String]
wcL :: [String] -> [String]
uniq :: String -> String
Documentation
abspath :: FilePath -> IO FilePathSource
Return the absolute path of the arg. Raises an error if the computation is impossible.
appendTo :: FilePath -> String -> IO StringSource
Like catTo, but appends to the file.
basename :: FilePath -> FilePathSource
The filename part of a path
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] -> String -> IO StringSource

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 read.

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.

catFromBS :: [FilePath] -> ByteString -> IO ByteStringSource
Lazy ByteString version of catFrom. This may have performance benefits.
catTo :: FilePath -> String -> IO StringSource
Takes input, writes it to the specified file, and does not pass it on. The return value is the empty string. See also catToBS, tee.
catToBS :: FilePath -> ByteString -> IO ByteStringSource
Like catTo, but operates in a lazy ByteString. This could be a performance benefit.
cd :: FilePath -> IO ()Source

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.

dirname :: FilePath -> FilePathSource
The directory part of a path
echo :: String -> String -> StringSource

Takes a string and sends it on as standard output.

The input to this function is never read.

See also echoBS.

echoBS :: ByteString -> ByteString -> ByteStringSource
ByteString.Lazy version of echo.
exit :: Int -> IO aSource
Exits with the specified error code. 0 indicates no error.
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.
joinLines :: [String] -> [String]Source
Join lines of a file
lower :: String -> StringSource
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.

numberLines :: [String] -> [String]Source
Number each line of a file
pwd :: IO FilePathSource
An alias for System.Directory.getCurrentDirectory.
readlink :: FilePath -> IO FilePathSource

Return the destination that the given symlink points to.

An alias for System.Posix.Files.readSymbolicLink

readlinkabs :: FilePath -> IO FilePathSource
As readlink, but turns the result into an absolute path.
rev :: [String] -> [String]Source
revW :: [String] -> [String]Source
Reverse characters on each line (rev)
space :: [String] -> [String]Source
unspace :: [String] -> [String]Source
Double space a file
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] -> String -> IO StringSource

Takes input, writes it to all the specified files, and passes it on. This function buffers the input.

See also teeBS, catFrom.

teeBS :: [FilePath] -> ByteString -> IO ByteStringSource
Lazy ByteString version of tee.
tr :: Char -> Char -> String -> StringSource

Translate a character x to y, like: 

tr 'e' 'f'

Or, in sed, 

y//
trd :: Char -> String -> StringSource
Delete specified character in a string.
wcW :: [String] -> [String]Source
Count number of lines. wc -l
wcL :: [String] -> [String]Source
uniq :: String -> StringSource

Remove duplicate lines from a file (like Unix uniq).

Takes a String representing a file or output and plugs it through lines and then nub to uniqify on a line basis.

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