io

The io operation module extends lua's built-in io module to provide more easy-to-use interfaces.

io.open

Open file for reading and writing

This is a native interface for lua. For detailed usage, see Lua's official documentation: The Complete I/O Model

If you want to read all the contents of the file, you can write:

local file = io.open("$(tmpdir)/file.txt", "r")
if file then
    local data = file:read("*all")
    file:close()
end

Or you can read it more quickly using io.readfile.

If you want to write a file, you can do this:

-- Open file: w is write mode, a is append write mode
local file = io.open("xxx.txt", "w")
if file then

    -- Write data to file with native lua interface, does not support formatting, no line breaks, does not support built-in variables
    file:write("hello xmake\n")

    -- Write data to file with xmake extended interface, support formatting, no line breaks, no built-in variables
    file:writef("hello %s\n", "xmake")

    -- Use xmake extended formatted parameters to write to one line, with line breaks, and support for built-in variables
    file:print("hello %s and $(buildir)", "xmake")

    -- Write a line using the xmake extended formatted arguments, no line breaks, and support for built-in variables
    file:printf("hello %s and $(buildir) \n", "xmake")

    -- Close the file
    file:close()
end

io.load

Load all table contents from the specified path file deserialization

You can load serialized table contents from a file, generally used with io.save, for example:

-- Load the contents of the serialized file to the table
local data = io.load("xxx.txt")
if data then

    -- Dump prints the contents of the entire table in the terminal, formatting the output
    utils.dump(data)
end

io.save

Serialize all table contents to the specified path file

You can serialize the contents of the table to the specified file, generally used in conjunction with io.load, for example:

io.save("xxx.txt", {a = "a", b = "b", c = "c"})

The result of the storage is:

{
    ["b"] = "b"
,   ["a"] = "a"
,   ["c"] = "c"
}

io.readfile

Read everything from the specified path file

It is more convenient to directly read the contents of the entire file without opening the file, for example:

local data = io.readfile("xxx.txt")

io.writefile

Write all content to the specified path file

It is more convenient to directly write the contents of the entire file without opening the file, for example:

io.writefile("xxx.txt", "all data")

io.gsub

Full text replaces the contents of the specified path file

Similar to the string.gsub interface, the full-text pattern matches the replacement content, but here is the direct operation file, for example:

-- Remove all whitespace characters from the file
io.gsub("xxx.txt", "%s+", "")

io.tail

Read and display the tail content of the file

Reads the data of the specified number of lines at the end of the file and displays a command like cat xxx.txt | tail -n 10, for example:

-- Display the last 10 lines of the file
io.tail("xxx.txt", 10)

io.cat

read and display all contents of the file

Read all the contents of the file and display it, similar to the cat xxx.txt command, for example:

io.cat("xxx.txt")

io.print

Formatted output content to file with newline

Directly format the passed parameter to output a line of string to the file with a line break, for example:

io.print("xxx.txt", "hello %s!", "xmake")

io.printf

Formatted output to file without line breaks

Directly format the passed parameter to output a line of string to the file without a line break, for example:

io.printf("xxx.txt", "hello %s!\n", "xmake")

io.lines

Read all lines from file

Returns all lines from a given file name

local lines = io.lines("xxx.txt")
for line in lines do
    print(line)
end

io.stdfile

Get a std file

Returns a file for a given std file name

-- returns stdin
io.stdin
-- returns stdout
io.stdout
-- returns stderr
io.stderr

io.openlock

Open a lock of a file

Returns a file lock object when successfully locking the file

local lock = io.openlock("xxx.txt")
lock:lock()
lock:unlock()
lock:close()

io.replace

Replace text of the given file and return the replaced data

Replaces a given pattern in a file by a replacement string

-- replace string "Hello" in "xxx.txt" with "World"
io.replace("xxx.txt", "Hello", "World")
-- if you want to replace a string and not a pattern
io.replace("xxx.txt", "1+1=2", "2+2=4", {plain = true})

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