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Return the absolute path of the arg. Raises an error if the computation is impossible.

Like catTo, but appends to the file.

The filename part of a path

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.

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 .

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

Generic version of catBytes; reads data from specified Handle, and ignores stdin.

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

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.

Split a list by a given character and select the nth list.

 cut ' ' 2 "foo bar baz quux" -> "bar"

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.

The directory part of a path

Read all input and produce no output. Discards input completely.

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.

Exits with the specified error code. 0 indicates no error.

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.

Search for the string in the lines. Return those that match. Same as:

 grep needle = filter (isInfixOf needle)

Search for the string in the lines. Return those that do NOT match.

Search for the regexp in the lines. Return those that match.

Search for the regexp in the lines. Return those that do NOT match.

Join lines of a file

Inverse of double space; drop empty lines

Convert a string to all upper or lower case

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.

Number each line of a file

An alias for System.Directory.getCurrentDirectory.

Return the destination that the given symlink points to.

An alias for System.Posix.Files.readSymbolicLink

This function is only available on POSIX platforms.

As readlink, but turns the result into an absolute path.

This function is only available on POSIX platforms.

Reverse characters on each line (rev)

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.

Double space a file

Reverse words on each line

Reverse lines in a String (like Unix tac).

Implemented as:

 tac = reverse

See uniq.

Takes input, writes it to all the specified files, and passes it on. This function does /NOT' buffer input.

See also catFrom.

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.

Translate a character x to y, like:

tr 'e' 'f'

Or, in sed,

y//

Delete specified character in a string.

Count number of lines. wc -l

Removes an environment variable if it exists; does nothing otherwise.

See also setenv, which has a more extensive example.

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.