os

This module contains basic operating system facilities like retrieving environment variables, reading command line arguments, working with directories, running shell commands, etc.

import os

let myFile = "/path/to/my/file.nim"

let pathSplit = splitPath(myFile)
assert pathSplit.head == "/path/to/my"
assert pathSplit.tail == "file.nim"

assert parentDir(myFile) == "/path/to/my"

let fileSplit = splitFile(myFile)
assert fileSplit.dir == "/path/to/my"
assert fileSplit.name == "file"
assert fileSplit.ext == ".nim"

assert myFile.changeFileExt("c") == "/path/to/my/file.c"

See also:

Imports

since, strutils, pathnorm, posix, times

Types

ReadEnvEffect = object of ReadIOEffect
Effect that denotes a read from an environment variable. Source Edit 
WriteEnvEffect = object of WriteIOEffect
Effect that denotes a write to an environment variable. Source Edit 
ReadDirEffect = object of ReadIOEffect
Effect that denotes a read operation from the directory structure. Source Edit 
WriteDirEffect = object of WriteIOEffect
Effect that denotes a write operation to the directory structure. Source Edit 
OSErrorCode = distinct int32
Specifies an OS Error Code. Source Edit 
FilePermission = enum
  fpUserExec,               ## execute access for the file owner
  fpUserWrite,              ## write access for the file owner
  fpUserRead,               ## read access for the file owner
  fpGroupExec,              ## execute access for the group
  fpGroupWrite,             ## write access for the group
  fpGroupRead,              ## read access for the group
  fpOthersExec,             ## execute access for others
  fpOthersWrite,            ## write access for others
  fpOthersRead               ## read access for others

File access permission, modelled after UNIX.

See also:

Source Edit 
PathComponent = enum
  pcFile,                   ## path refers to a file
  pcLinkToFile,             ## path refers to a symbolic link to a file
  pcDir,                    ## path refers to a directory
  pcLinkToDir                ## path refers to a symbolic link to a directory

Enumeration specifying a path component.

See also:

Source Edit 
DeviceId = Dev
Source Edit 
FileId = Ino
Source Edit 
FileInfo = object
  id*: tuple[device: DeviceId, file: FileId] ## Device and file id.
  kind*: PathComponent       ## Kind of file object - directory, symlink, etc.
  size*: BiggestInt          ## Size of file.
  permissions*: set[FilePermission] ## File permissions
  linkCount*: BiggestInt     ## Number of hard links the file object has.
  lastAccessTime*: times.Time ## Time file was last accessed.
  lastWriteTime*: times.Time ## Time file was last modified/written to.
  creationTime*: times.Time  ## Time file was created. Not supported on all systems!

Contains information associated with a file object.

See also:

Source Edit

Consts

invalidFilenameChars = {'/', '\\', ':', '*', '?', '\"', '<', '>', '|', '^',
                        '\x00'}
Characters that may produce invalid filenames across Linux, Windows, Mac, etc. You can check if your filename contains these char and strip them for safety. Mac bans ':', Linux bans '/', Windows bans all others. Source Edit 
invalidFilenames = ["CON", "PRN", "AUX", "NUL", "COM0", "COM1", "COM2", "COM3",
                    "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "LPT0",
                    "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7",
                    "LPT8", "LPT9"]
Filenames that may be invalid across Linux, Windows, Mac, etc. You can check if your filename match these and rename it for safety (Currently all invalid filenames are from Windows only). Source Edit 
doslikeFileSystem = false
Source Edit 
CurDir = '.'

The constant character used by the operating system to refer to the current directory.

For example: '.' for POSIX or ':' for the classic Macintosh.

Source Edit 
ParDir = ".."

The constant string used by the operating system to refer to the parent directory.

For example: ".." for POSIX or "::" for the classic Macintosh.

Source Edit 
DirSep = '/'
The character used by the operating system to separate pathname components, for example: '/' for POSIX, ':' for the classic Macintosh, and '\' on Windows. Source Edit 
AltSep = '/'
An alternative character used by the operating system to separate pathname components, or the same as DirSep if only one separator character exists. This is set to '/' on Windows systems where DirSep is a backslash ('\'). Source Edit 
PathSep = ':'
The character conventionally used by the operating system to separate search patch components (as in PATH), such as ':' for POSIX or ';' for Windows. Source Edit 
FileSystemCaseSensitive = true
True if the file system is case sensitive, false otherwise. Used by cmpPaths proc to compare filenames properly. Source Edit 
ExeExt = ""
The file extension of native executables. For example: "" for POSIX, "exe" on Windows (without a dot). Source Edit 
ScriptExt = ""
The file extension of a script file. For example: "" for POSIX, "bat" on Windows. Source Edit 
DynlibFormat = "lib$1.so"
The format string to turn a filename into a DLL file (also called shared object on some operating systems). Source Edit 
ExtSep = '.'
The character which separates the base filename from the extension; for example, the '.' in os.nim. Source Edit 
ExeExts = [""]
Platform specific file extension for executables. On Windows ["exe", "cmd", "bat"], on Posix [""]. Source Edit

Procs

proc normalizePathEnd(path: var string; trailingSep = false) {...}{.raises: [],
    tags: [].}
Ensures path has exactly 0 or 1 trailing DirSep, depending on trailingSep, and taking care of edge cases: it preservers whether a path is absolute or relative, and makes sure trailing sep is DirSep, not AltSep. Trailing /. are compressed, see examples. Source Edit 
proc normalizePathEnd(path: string; trailingSep = false): string {...}{.raises: [],
    tags: [].}
outplace overload

Example:

when defined(posix):
  assert normalizePathEnd("/lib//.//", trailingSep = true) == "/lib/"
  assert normalizePathEnd("lib/./.", trailingSep = false) == "lib"
  assert normalizePathEnd(".//./.", trailingSep = false) == "."
  assert normalizePathEnd("", trailingSep = true) == "" # not / !
  assert normalizePathEnd("/", trailingSep = false) == "/" # not "" !
Source Edit 
proc joinPath(head, tail: string): string {...}{.noSideEffect, gcsafe,
    extern: "nos$1", raises: [], tags: [].}

Joins two directory names to one.

returns normalized path concatenation of head and tail, preserving whether or not tail has a trailing slash (or, if tail if empty, whether head has one).

See also:

Example:

when defined(posix):
  assert joinPath("usr", "lib") == "usr/lib"
  assert joinPath("usr", "lib/") == "usr/lib/"
  assert joinPath("usr", "") == "usr"
  assert joinPath("usr/", "") == "usr/"
  assert joinPath("", "") == ""
  assert joinPath("", "lib") == "lib"
  assert joinPath("", "/lib") == "/lib"
  assert joinPath("usr/", "/lib") == "usr/lib"
  assert joinPath("usr/lib", "../bin") == "usr/bin"
Source Edit 
proc joinPath(parts: varargs[string]): string {...}{.noSideEffect, gcsafe,
    extern: "nos$1OpenArray", raises: [], tags: [].}

The same as joinPath(head, tail) proc, but works with any number of directory parts.

You need to pass at least one element or the proc will assert in debug builds and crash on release builds.

See also:

Example:

when defined(posix):
  assert joinPath("a") == "a"
  assert joinPath("a", "b", "c") == "a/b/c"
  assert joinPath("usr/lib", "../../var", "log") == "var/log"
Source Edit 
proc `/`(head, tail: string): string {...}{.noSideEffect, raises: [], tags: [].}

The same as joinPath(head, tail) proc.

See also:

Example:

when defined(posix):
  assert "usr" / "" == "usr"
  assert "" / "lib" == "lib"
  assert "" / "/lib" == "/lib"
  assert "usr/" / "/lib/" == "usr/lib/"
  assert "usr" / "lib" / "../bin" == "usr/bin"
Source Edit 
proc splitPath(path: string): tuple[head, tail: string] {...}{.noSideEffect, gcsafe,
    extern: "nos$1", raises: [], tags: [].}

Splits a directory into (head, tail) tuple, so that head / tail == path (except for edge cases like "/usr").

See also:

Example:

assert splitPath("usr/local/bin") == ("usr/local", "bin")
assert splitPath("usr/local/bin/") == ("usr/local/bin", "")
assert splitPath("/bin/") == ("/bin", "")
when (NimMajor, NimMinor) <= (1, 0):
  assert splitPath("/bin") == ("", "bin")
else:
  assert splitPath("/bin") == ("/", "bin")
assert splitPath("bin") == ("", "bin")
assert splitPath("") == ("", "")
Source Edit 
proc isAbsolute(path: string): bool {...}{.gcsafe, noSideEffect, extern: "nos$1",
                                      raises: [], tags: [].}

Checks whether a given path is absolute.

On Windows, network paths are considered absolute too.

Example:

assert not "".isAbsolute
assert not ".".isAbsolute
when defined(posix):
  assert "/".isAbsolute
  assert not "a/".isAbsolute
  assert "/a/".isAbsolute
Source Edit 
proc relativePath(path, base: string; sep = DirSep): string {...}{.gcsafe,
    extern: "nos$1", raises: [Exception], tags: [RootEffect].}

Converts path to a path relative to base.

The sep (default: DirSep) is used for the path normalizations, this can be useful to ensure the relative path only contains '/' so that it can be used for URL constructions.

On windows, if a root of path and a root of base are different, returns path as is because it is impossible to make a relative path. That means an absolute path can be returned.

See also:

Example:

assert relativePath("/Users/me/bar/z.nim", "/Users/other/bad", '/') == "../../me/bar/z.nim"
assert relativePath("/Users/me/bar/z.nim", "/Users/other", '/') == "../me/bar/z.nim"
assert relativePath("/Users///me/bar//z.nim", "//Users/", '/') == "me/bar/z.nim"
assert relativePath("/Users/me/bar/z.nim", "/Users/me", '/') == "bar/z.nim"
assert relativePath("", "/users/moo", '/') == ""
assert relativePath("foo", ".", '/') == "foo"
assert relativePath("foo", "foo", '/') == "."
Source Edit 
proc isRelativeTo(path: string; base: string): bool {...}{.raises: [Exception],
    tags: [RootEffect].}
Returns true if path is relative to base.

Example:

doAssert isRelativeTo("./foo//bar", "foo")
doAssert isRelativeTo("foo/bar", ".")
doAssert isRelativeTo("/foo/bar.nim", "/foo/bar.nim")
doAssert not isRelativeTo("foo/bar.nims", "foo/bar.nim")
Source Edit 
proc parentDir(path: string): string {...}{.noSideEffect, gcsafe, extern: "nos$1",
                                       raises: [], tags: [].}

Returns the parent directory of path.

This is similar to splitPath(path).head when path doesn't end in a dir separator, but also takes care of path normalizations. The remainder can be obtained with lastPathPart(path) proc.

See also:

Example:

assert parentDir("") == ""
when defined(posix):
  assert parentDir("/usr/local/bin") == "/usr/local"
  assert parentDir("foo/bar//") == "foo"
  assert parentDir("//foo//bar//.") == "/foo"
  assert parentDir("./foo") == "."
  assert parentDir("/./foo//./") == "/"
  assert parentDir("a//./") == "."
  assert parentDir("a/b/c/..") == "a"
Source Edit 
proc tailDir(path: string): string {...}{.noSideEffect, gcsafe, extern: "nos$1",
                                     raises: [], tags: [].}

Returns the tail part of path.

See also:

Example:

assert tailDir("/bin") == "bin"
assert tailDir("bin") == ""
assert tailDir("bin/") == ""
assert tailDir("/usr/local/bin") == "usr/local/bin"
assert tailDir("//usr//local//bin//") == "usr//local//bin//"
assert tailDir("./usr/local/bin") == "usr/local/bin"
assert tailDir("usr/local/bin") == "local/bin"
Source Edit 
proc isRootDir(path: string): bool {...}{.noSideEffect, gcsafe, extern: "nos$1",
                                     raises: [], tags: [].}
Checks whether a given path is a root directory.

Example:

assert isRootDir("")
assert isRootDir(".")
assert isRootDir("/")
assert isRootDir("a")
assert not isRootDir("/a")
assert not isRootDir("a/b/c")
Source Edit 
proc `/../`(head, tail: string): string {...}{.noSideEffect, raises: [], tags: [].}

The same as parentDir(head) / tail, unless there is no parent directory. Then head / tail is performed instead.

See also:

Example:

when defined(posix):
  assert "a/b/c" /../ "d/e" == "a/b/d/e"
  assert "a" /../ "d/e" == "a/d/e"
Source Edit 
proc searchExtPos(path: string): int {...}{.raises: [], tags: [].}

Returns index of the '.' char in path if it signifies the beginning of extension. Returns -1 otherwise.

See also:

Example:

assert searchExtPos("a/b/c") == -1
assert searchExtPos("c.nim") == 1
assert searchExtPos("a/b/c.nim") == 5
assert searchExtPos("a.b.c.nim") == 5
Source Edit 
proc splitFile(path: string): tuple[dir, name, ext: string] {...}{.noSideEffect,
    gcsafe, extern: "nos$1", raises: [], tags: [].}

Splits a filename into (dir, name, extension) tuple.

dir does not end in DirSep unless it's /. extension includes the leading dot.

If path has no extension, ext is the empty string. If path has no directory component, dir is the empty string. If path has no filename component, name and ext are empty strings.

See also:

Example:

var (dir, name, ext) = splitFile("usr/local/nimc.html")
assert dir == "usr/local"
assert name == "nimc"
assert ext == ".html"
(dir, name, ext) = splitFile("/usr/local/os")
assert dir == "/usr/local"
assert name == "os"
assert ext == ""
(dir, name, ext) = splitFile("/usr/local/")
assert dir == "/usr/local"
assert name == ""
assert ext == ""
(dir, name, ext) = splitFile("/tmp.txt")
assert dir == "/"
assert name == "tmp"
assert ext == ".txt"
Source Edit 
proc extractFilename(path: string): string {...}{.noSideEffect, gcsafe,
    extern: "nos$1", raises: [], tags: [].}

Extracts the filename of a given path.

This is the same as name & ext from splitFile(path) proc.

See also:

Example:

assert extractFilename("foo/bar/") == ""
assert extractFilename("foo/bar") == "bar"
assert extractFilename("foo/bar.baz") == "bar.baz"
Source Edit 
proc lastPathPart(path: string): string {...}{.noSideEffect, gcsafe, extern: "nos$1",
    raises: [], tags: [].}

Like extractFilename proc, but ignores trailing dir separator; aka: baseName in some other languages.

See also:

Example:

assert lastPathPart("foo/bar/") == "bar"
assert lastPathPart("foo/bar") == "bar"
Source Edit 
proc changeFileExt(filename, ext: string): string {...}{.noSideEffect, gcsafe,
    extern: "nos$1", raises: [], tags: [].}

Changes the file extension to ext.

If the filename has no extension, ext will be added. If ext == "" then any extension is removed.

Ext should be given without the leading '.', because some filesystems may use a different character. (Although I know of none such beast.)

See also:

Example:

assert changeFileExt("foo.bar", "baz") == "foo.baz"
assert changeFileExt("foo.bar", "") == "foo"
assert changeFileExt("foo", "baz") == "foo.baz"
Source Edit 
proc addFileExt(filename, ext: string): string {...}{.noSideEffect, gcsafe,
    extern: "nos$1", raises: [], tags: [].}

Adds the file extension ext to filename, unless filename already has an extension.

Ext should be given without the leading '.', because some filesystems may use a different character. (Although I know of none such beast.)

See also:

Example:

assert addFileExt("foo.bar", "baz") == "foo.bar"
assert addFileExt("foo.bar", "") == "foo.bar"
assert addFileExt("foo", "baz") == "foo.baz"
Source Edit 
proc cmpPaths(pathA, pathB: string): int {...}{.noSideEffect, gcsafe,
    extern: "nos$1", raises: [], tags: [].}

Compares two paths.

On a case-sensitive filesystem this is done case-sensitively otherwise case-insensitively. Returns:

0 if pathA == pathB
< 0 if pathA < pathB
> 0 if pathA > pathB

Example:

when defined(macosx):
  assert cmpPaths("foo", "Foo") == 0
elif defined(posix):
  assert cmpPaths("foo", "Foo") > 0
Source Edit 
proc unixToNativePath(path: string; drive = ""): string {...}{.noSideEffect, gcsafe,
    extern: "nos$1", raises: [], tags: [].}

Converts an UNIX-like path to a native one.

On an UNIX system this does nothing. Else it converts '/', '.', '..' to the appropriate things.

On systems with a concept of "drives", drive is used to determine which drive label to use during absolute path conversion. drive defaults to the drive of the current working directory, and is ignored on systems that do not have a concept of "drives".

Source Edit 
proc `==`(err1, err2: OSErrorCode): bool {...}{.borrow.}
Source Edit 
proc `$`(err: OSErrorCode): string {...}{.borrow.}
Source Edit 
proc osErrorMsg(errorCode: OSErrorCode): string {...}{.raises: [], tags: [].}

Converts an OS error code into a human readable string.

The error code can be retrieved using the osLastError proc.

If conversion fails, or errorCode is 0 then "" will be returned.

On Windows, the -d:useWinAnsi compilation flag can be used to make this procedure use the non-unicode Win API calls to retrieve the message.

See also:

Example:

when defined(linux):
  assert osErrorMsg(OSErrorCode(0)) == ""
  assert osErrorMsg(OSErrorCode(1)) == "Operation not permitted"
  assert osErrorMsg(OSErrorCode(2)) == "No such file or directory"
Source Edit 
proc newOSError(errorCode: OSErrorCode; additionalInfo = ""): owned(ref OSError) {...}{.
    noinline, raises: [], tags: [].}

Creates a new OSError exception.

The errorCode will determine the message, osErrorMsg proc will be used to get this message.

The error code can be retrieved using the osLastError proc.

If the error code is 0 or an error message could not be retrieved, the message unknown OS error will be used.

See also:

Source Edit 
proc raiseOSError(errorCode: OSErrorCode; additionalInfo = "") {...}{.noinline,
    raises: [OSError], tags: [].}

Raises an OSError exception.

Read the description of the newOSError proc to learn how the exception object is created.

Source Edit 
proc osLastError(): OSErrorCode {...}{.sideEffect, raises: [], tags: [].}

Retrieves the last operating system error code.

This procedure is useful in the event when an OS call fails. In that case this procedure will return the error code describing the reason why the OS call failed. The OSErrorMsg procedure can then be used to convert this code into a string.

Warning: The behaviour of this procedure varies between Windows and POSIX systems. On Windows some OS calls can reset the error code to 0 causing this procedure to return 0. It is therefore advised to call this procedure immediately after an OS call fails. On POSIX systems this is not a problem.

See also:

Source Edit 
proc getEnv(key: string; default = ""): TaintedString {...}{.tags: [ReadEnvEffect],
    raises: [].}

Returns the value of the environment variable named key.

If the variable does not exist, "" is returned. To distinguish whether a variable exists or it's value is just "", call existsEnv(key) proc.

See also:

Example:

assert getEnv("unknownEnv") == ""
assert getEnv("unknownEnv", "doesn't exist") == "doesn't exist"
Source Edit 
proc existsEnv(key: string): bool {...}{.tags: [ReadEnvEffect], raises: [].}

Checks whether the environment variable named key exists. Returns true if it exists, false otherwise.

See also:

Example:

assert not existsEnv("unknownEnv")
Source Edit 
proc putEnv(key, val: string) {...}{.tags: [WriteEnvEffect], raises: [OSError].}

Sets the value of the environment variable named key to val. If an error occurs, OSError is raised.

See also:

Source Edit 
proc delEnv(key: string) {...}{.tags: [WriteEnvEffect], raises: [OSError].}

Deletes the environment variable named key. If an error occurs, OSError is raised.

See also:ven

Source Edit 
proc getHomeDir(): string {...}{.gcsafe, extern: "nos$1",
                            tags: [ReadEnvEffect, ReadIOEffect], raises: [].}

Returns the home directory of the current user.

This proc is wrapped by the expandTilde proc for the convenience of processing paths coming from user configuration files.

See also:

Example:

assert getHomeDir() == expandTilde("~")
Source Edit 
proc getConfigDir(): string {...}{.gcsafe, extern: "nos$1",
                              tags: [ReadEnvEffect, ReadIOEffect], raises: [].}

Returns the config directory of the current user for applications.

On non-Windows OSs, this proc conforms to the XDG Base Directory spec. Thus, this proc returns the value of the XDG_CONFIG_HOME environment variable if it is set, otherwise it returns the default configuration directory ("~/.config/").

An OS-dependent trailing slash is always present at the end of the returned string: \ on Windows and / on all other OSs.

See also:

Source Edit 
proc getTempDir(): string {...}{.gcsafe, extern: "nos$1",
                            tags: [ReadEnvEffect, ReadIOEffect], raises: [].}

Returns the temporary directory of the current user for applications to save temporary files in.

Please do not use this: On Android, it currently returns getHomeDir(), and on other Unix based systems it can cause security problems too. That said, you can override this implementation by adding -d:tempDir=mytempname to your compiler invocation.

See also:

Source Edit 
proc expandTilde(path: string): string {...}{.tags: [ReadEnvEffect, ReadIOEffect],
    raises: [].}

Expands ~ or a path starting with ~/ to a full path, replacing ~ with getHomeDir() (otherwise returns path unmodified).

Windows: this is still supported despite Windows platform not having this convention; also, both ~/ and ~\ are handled.

Warning: ~bob and ~bob/ are not yet handled correctly.

See also:

Example:

assert expandTilde("~" / "appname.cfg") == getHomeDir() / "appname.cfg"
assert expandTilde("~/foo/bar") == getHomeDir() / "foo/bar"
assert expandTilde("/foo/bar") == "/foo/bar"
Source Edit 
proc quoteShellWindows(s: string): string {...}{.noSideEffect, gcsafe,
    extern: "nosp$1", raises: [], tags: [].}

Quote s, so it can be safely passed to Windows API.

Based on Python's subprocess.list2cmdline. See this link for more details.

Source Edit 
proc quoteShellPosix(s: string): string {...}{.noSideEffect, gcsafe,
    extern: "nosp$1", raises: [], tags: [].}
Quote s, so it can be safely passed to POSIX shell. Based on Python's pipes.quote. Source Edit 
proc quoteShell(s: string): string {...}{.noSideEffect, gcsafe, extern: "nosp$1",
                                     raises: [], tags: [].}

Quote s, so it can be safely passed to shell.

When on Windows, it calls quoteShellWindows proc. Otherwise, calls quoteShellPosix proc.

Source Edit 
proc quoteShellCommand(args: openArray[string]): string {...}{.raises: [], tags: [].}
Concatenates and quotes shell arguments args.

Example:

when defined(posix):
  assert quoteShellCommand(["aaa", "", "c d"]) == "aaa '' 'c d'"
when defined(windows):
  assert quoteShellCommand(["aaa", "", "c d"]) == "aaa \"\" \"c d\""
Source Edit 
proc fileExists(filename: string): bool {...}{.gcsafe, extern: "nos$1",
    tags: [ReadDirEffect], raises: [].}

Returns true if filename exists and is a regular file or symlink.

Directories, device files, named pipes and sockets return false.

See also:

Source Edit 
proc dirExists(dir: string): bool {...}{.gcsafe, extern: "nos$1",
                                    tags: [ReadDirEffect], raises: [].}

Returns true if the directory dir exists. If dir is a file, false is returned. Follows symlinks.

See also:

Source Edit 
proc symlinkExists(link: string): bool {...}{.gcsafe, extern: "nos$1",
    tags: [ReadDirEffect], raises: [].}

Returns true if the symlink link exists. Will return true regardless of whether the link points to a directory or file.

See also:

Source Edit 
proc findExe(exe: string; followSymlinks: bool = true;
             extensions: openArray[string] = ExeExts): string {...}{.
    tags: [ReadDirEffect, ReadEnvEffect, ReadIOEffect], raises: [OSError].}

Searches for exe in the current working directory and then in directories listed in the PATH environment variable.

Returns "" if the exe cannot be found. exe is added the ExeExts file extensions if it has none.

If the system supports symlinks it also resolves them until it meets the actual file. This behavior can be disabled if desired by setting followSymlinks = false.

Source Edit 
proc getLastModificationTime(file: string): times.Time {...}{.gcsafe,
    extern: "nos$1", raises: [OSError], tags: [].}

Returns the file's last modification time.

See also:

Source Edit 
proc getLastAccessTime(file: string): times.Time {...}{.gcsafe, extern: "nos$1",
    raises: [OSError], tags: [].}

Returns the file's last read or write access time.

See also:

Source Edit 
proc getCreationTime(file: string): times.Time {...}{.gcsafe, extern: "nos$1",
    raises: [OSError], tags: [].}

Returns the file's creation time.

Note: Under POSIX OS's, the returned time may actually be the time at which the file's attribute's were last modified. See here for details.

See also:

Source Edit 
proc fileNewer(a, b: string): bool {...}{.gcsafe, extern: "nos$1", raises: [OSError],
                                     tags: [].}

Returns true if the file a is newer than file b, i.e. if a's modification time is later than b's.

See also:

Source Edit 
proc getCurrentDir(): string {...}{.gcsafe, extern: "nos$1", tags: [],
                               raises: [OSError].}

Returns the current working directory i.e. where the built binary is run.

So the path returned by this proc is determined at run time.

See also:

Source Edit 
proc setCurrentDir(newDir: string) {...}{.inline, tags: [], raises: [OSError].}

Sets the current working directory; OSError is raised if newDir cannot been set.

See also:

Source Edit 
proc absolutePath(path: string; root = getCurrentDir()): string {...}{.
    raises: [ValueError], tags: [].}

Returns the absolute path of path, rooted at root (which must be absolute; default: current directory). If path is absolute, return it, ignoring root.

See also:

Example:

assert absolutePath("a") == getCurrentDir() / "a"
Source Edit 
proc normalizeExe(file: var string) {...}{.raises: [], tags: [].}
on posix, prepends ./ if file doesn't contain / and is not "", ".", "..".

Example:

import sugar
when defined(posix):
  doAssert "foo".dup(normalizeExe) == "./foo"
  doAssert "foo/../bar".dup(normalizeExe) == "foo/../bar"
doAssert "".dup(normalizeExe) == ""
Source Edit 
proc normalizePath(path: var string) {...}{.gcsafe, extern: "nos$1", tags: [],
                                       raises: [].}

Normalize a path.

Consecutive directory separators are collapsed, including an initial double slash.

On relative paths, double dot (..) sequences are collapsed if possible. On absolute paths they are always collapsed.

Warning: URL-encoded and Unicode attempts at directory traversal are not detected. Triple dot is not handled.

See also:

Example:

when defined(posix):
  var a = "a///b//..//c///d"
  a.normalizePath()
  assert a == "a/c/d"
Source Edit 
proc normalizedPath(path: string): string {...}{.gcsafe, extern: "nos$1", tags: [],
    raises: [].}

Returns a normalized path for the current OS.

See also:

Example:

when defined(posix):
  assert normalizedPath("a///b//..//c///d") == "a/c/d"
Source Edit 
proc sameFile(path1, path2: string): bool {...}{.gcsafe, extern: "nos$1",
    tags: [ReadDirEffect], raises: [OSError].}

Returns true if both pathname arguments refer to the same physical file or directory.

Raises OSError if any of the files does not exist or information about it can not be obtained.

This proc will return true if given two alternative hard-linked or sym-linked paths to the same file or directory.

See also:

Source Edit 
proc sameFileContent(path1, path2: string): bool {...}{.gcsafe, extern: "nos$1",
    tags: [ReadIOEffect], raises: [IOError].}

Returns true if both pathname arguments refer to files with identical binary content.

See also:

Source Edit 
proc getFilePermissions(filename: string): set[FilePermission] {...}{.gcsafe,
    extern: "nos$1", tags: [ReadDirEffect], raises: [OSError].}

Retrieves file permissions for filename.

OSError is raised in case of an error. On Windows, only the readonly flag is checked, every other permission is available in any case.

See also:

Source Edit 
proc setFilePermissions(filename: string; permissions: set[FilePermission]) {...}{.
    gcsafe, extern: "nos$1", tags: [WriteDirEffect], raises: [OSError].}

Sets the file permissions for filename.

OSError is raised in case of an error. On Windows, only the readonly flag is changed, depending on fpUserWrite permission.

See also:

Source Edit 
proc copyFile(source, dest: string) {...}{.gcsafe, extern: "nos$1",
                                      tags: [ReadIOEffect, WriteIOEffect],
                                      raises: [OSError, IOError].}

Copies a file from source to dest, where dest.parentDir must exist.

If this fails, OSError is raised.

On the Windows platform this proc will copy the source file's attributes into dest.

On other platforms you need to use getFilePermissions and setFilePermissions procs to copy them by hand (or use the convenience copyFileWithPermissions proc), otherwise dest will inherit the default permissions of a newly created file for the user.

If dest already exists, the file attributes will be preserved and the content overwritten.

See also:

Source Edit 
proc copyFileToDir(source, dir: string) {...}{.
    raises: [ValueError, OSError, IOError], tags: [ReadIOEffect, WriteIOEffect].}
Copies a file source into directory dir, which must exist. Source Edit 
proc tryRemoveFile(file: string): bool {...}{.gcsafe, extern: "nos$1",
    tags: [WriteDirEffect], raises: [].}

Removes the file.

If this fails, returns false. This does not fail if the file never existed in the first place.

On Windows, ignores the read-only attribute.

See also:

Source Edit 
proc removeFile(file: string) {...}{.gcsafe, extern: "nos$1", tags: [WriteDirEffect],
                                raises: [OSError].}

Removes the file.

If this fails, OSError is raised. This does not fail if the file never existed in the first place.

On Windows, ignores the read-only attribute.

See also:

Source Edit 
proc moveFile(source, dest: string) {...}{.gcsafe, extern: "nos$1",
                                      tags: [ReadIOEffect, WriteIOEffect],
                                      raises: [OSError, IOError, Exception].}

Moves a file from source to dest.

If this fails, OSError is raised. If dest already exists, it will be overwritten.

Can be used to rename files.

See also:

Source Edit 
proc exitStatusLikeShell(status: cint): cint {...}{.raises: [], tags: [].}
Converts exit code from c_system into a shell exit code. Source Edit 
proc execShellCmd(command: string): int {...}{.gcsafe, extern: "nos$1",
    tags: [ExecIOEffect], raises: [].}

Executes a shell command.

Command has the form 'program args' where args are the command line arguments given to program. The proc returns the error code of the shell when it has finished (zero if there is no error). The proc does not return until the process has finished.

To execute a program without having a shell involved, use osproc.execProcess proc.

Examples:

discard execShellCmd("ls -la")
Source Edit 
proc expandFilename(filename: string): string {...}{.gcsafe, extern: "nos$1",
    tags: [ReadDirEffect], raises: [OSError].}

Returns the full (absolute) path of an existing file filename.

Raises OSError in case of an error. Follows symlinks.

Source Edit 
proc getCurrentCompilerExe(): string {...}{.compileTime, raises: [], tags: [].}

This is getAppFilename() at compile time.

Can be used to retrieve the currently executing Nim compiler from a Nim or nimscript program, or the nimble binary inside a nimble program (likewise with other binaries built from compiler API).

Source Edit 
proc removeDir(dir: string; checkDir = false) {...}{.gcsafe, extern: "nos$1",
    tags: [WriteDirEffect, ReadDirEffect], gcsafe, locks: 0, raises: [OSError].}

Removes the directory dir including all subdirectories and files in dir (recursively).

If this fails, OSError is raised. This does not fail if the directory never existed in the first place, unless checkDir = true

See also:

Source Edit 
proc existsOrCreateDir(dir: string): bool {...}{.gcsafe, extern: "nos$1",
    tags: [WriteDirEffect, ReadDirEffect], raises: [OSError, IOError].}

Check if a directory dir exists, and create it otherwise.

Does not create parent directories (fails if parent does not exist). Returns true if the directory already exists, and false otherwise.

See also:

Source Edit 
proc createDir(dir: string) {...}{.gcsafe, extern: "nos$1",
                              tags: [WriteDirEffect, ReadDirEffect],
                              raises: [OSError, IOError].}

Creates the directory dir.

The directory may contain several subdirectories that do not exist yet. The full path is created. If this fails, OSError is raised.

It does not fail if the directory already exists because for most usages this does not indicate an error.

See also:

Source Edit 
proc copyDir(source, dest: string) {...}{.gcsafe, extern: "nos$1",
                                     tags: [WriteIOEffect, ReadIOEffect],
                                     gcsafe, locks: 0,
                                     raises: [OSError, IOError].}

Copies a directory from source to dest.

If this fails, OSError is raised.

On the Windows platform this proc will copy the attributes from source into dest.

On other platforms created files and directories will inherit the default permissions of a newly created file/directory for the user. Use copyDirWithPermissions proc to preserve attributes recursively on these platforms.

See also:

Source Edit 
proc moveDir(source, dest: string) {...}{.tags: [ReadIOEffect, WriteIOEffect],
                                     raises: [OSError, IOError].}

Moves a directory from source to dest.

If this fails, OSError is raised.

See also:

Source Edit 
proc createSymlink(src, dest: string) {...}{.raises: [OSError], tags: [].}

Create a symbolic link at dest which points to the item specified by src. On most operating systems, will fail if a link already exists.

Warning: Some OS's (such as Microsoft Windows) restrict the creation of symlinks to root users (administrators).

See also:

Source Edit 
proc createHardlink(src, dest: string) {...}{.raises: [OSError], tags: [].}

Create a hard link at dest which points to the item specified by src.

Warning: Some OS's restrict the creation of hard links to root users (administrators).

See also:

Source Edit 
proc copyFileWithPermissions(source, dest: string; ignorePermissionErrors = true) {...}{.
    raises: [OSError, IOError, Exception],
    tags: [ReadIOEffect, WriteIOEffect, WriteDirEffect, ReadDirEffect].}

Copies a file from source to dest preserving file permissions.

This is a wrapper proc around copyFile, getFilePermissions and setFilePermissions procs on non-Windows platforms.

On Windows this proc is just a wrapper for copyFile proc since that proc already copies attributes.

On non-Windows systems permissions are copied after the file itself has been copied, which won't happen atomically and could lead to a race condition. If ignorePermissionErrors is true (default), errors while reading/setting file attributes will be ignored, otherwise will raise OSError.

See also:

Source Edit 
proc copyDirWithPermissions(source, dest: string; ignorePermissionErrors = true) {...}{.
    gcsafe, extern: "nos$1", tags: [WriteIOEffect, ReadIOEffect], gcsafe,
    locks: 0, raises: [OSError, IOError, Exception].}

Copies a directory from source to dest preserving file permissions.

If this fails, OSError is raised. This is a wrapper proc around copyDir and copyFileWithPermissions procs on non-Windows platforms.

On Windows this proc is just a wrapper for copyDir proc since that proc already copies attributes.

On non-Windows systems permissions are copied after the file or directory itself has been copied, which won't happen atomically and could lead to a race condition. If ignorePermissionErrors is true (default), errors while reading/setting file attributes will be ignored, otherwise will raise OSError.

See also:

Source Edit 
proc inclFilePermissions(filename: string; permissions: set[FilePermission]) {...}{.
    gcsafe, extern: "nos$1", tags: [ReadDirEffect, WriteDirEffect],
    raises: [OSError].}
A convenience proc for:
setFilePermissions(filename, getFilePermissions(filename)+permissions)
Source Edit 
proc exclFilePermissions(filename: string; permissions: set[FilePermission]) {...}{.
    gcsafe, extern: "nos$1", tags: [ReadDirEffect, WriteDirEffect],
    raises: [OSError].}
A convenience proc for:
setFilePermissions(filename, getFilePermissions(filename)-permissions)
Source Edit 
proc expandSymlink(symlinkPath: string): string {...}{.raises: [OSError], tags: [].}

Returns a string representing the path to which the symbolic link points.

On Windows this is a noop, symlinkPath is simply returned.

See also:

Source Edit 
proc parseCmdLine(c: string): seq[string] {...}{.noSideEffect, gcsafe,
    extern: "nos$1", raises: [], tags: [].}

Splits a command line into several components.

Note: This proc is only occasionally useful, better use the parseopt module.

On Windows, it uses the following parsing rules:

  • Arguments are delimited by white space, which is either a space or a tab.
  • The caret character (^) is not recognized as an escape character or delimiter. The character is handled completely by the command-line parser in the operating system before being passed to the argv array in the program.
  • A string surrounded by double quotation marks ("string") is interpreted as a single argument, regardless of white space contained within. A quoted string can be embedded in an argument.
  • A double quotation mark preceded by a backslash (") is interpreted as a literal double quotation mark character (").
  • Backslashes are interpreted literally, unless they immediately precede a double quotation mark.
  • If an even number of backslashes is followed by a double quotation mark, one backslash is placed in the argv array for every pair of backslashes, and the double quotation mark is interpreted as a string delimiter.
  • If an odd number of backslashes is followed by a double quotation mark, one backslash is placed in the argv array for every pair of backslashes, and the double quotation mark is "escaped" by the remaining backslash, causing a literal double quotation mark (") to be placed in argv.

On Posix systems, it uses the following parsing rules: Components are separated by whitespace unless the whitespace occurs within " or ' quotes.

See also:

Source Edit 
proc paramCount(): int {...}{.tags: [ReadIOEffect], raises: [].}

Returns the number of command line arguments given to the application.

Unlike argc in C, if your binary was called without parameters this will return zero. You can query each individual parameter with paramStr proc or retrieve all of them in one go with commandLineParams proc.

Availability: When generating a dynamic library (see --app:lib) on Posix this proc is not defined. Test for availability using declared().

See also:

Examples:

when declared(paramCount):
  # Use paramCount() here
else:
  # Do something else!
Source Edit 
proc paramStr(i: int): TaintedString {...}{.tags: [ReadIOEffect], raises: [].}

Returns the i-th command line argument given to the application.

i should be in the range 1..paramCount(), the IndexDefect exception will be raised for invalid values. Instead of iterating over paramCount() with this proc you can call the convenience commandLineParams().

Similarly to argv in C, it is possible to call paramStr(0) but this will return OS specific contents (usually the name of the invoked executable). You should avoid this and call getAppFilename() instead.

Availability: When generating a dynamic library (see --app:lib) on Posix this proc is not defined. Test for availability using declared().

See also:

Examples:

when declared(paramStr):
  # Use paramStr() here
else:
  # Do something else!
Source Edit 
proc commandLineParams(): seq[TaintedString] {...}{.raises: [], tags: [ReadIOEffect].}

Convenience proc which returns the command line parameters.

This returns only the parameters. If you want to get the application executable filename, call getAppFilename().

Availability: On Posix there is no portable way to get the command line from a DLL and thus the proc isn't defined in this environment. You can test for its availability with declared().

See also:

Examples:

when declared(commandLineParams):
  # Use commandLineParams() here
else:
  # Do something else!
Source Edit 
proc getAppFilename(): string {...}{.gcsafe, extern: "nos$1", tags: [ReadIOEffect],
                                raises: [].}

Returns the filename of the application's executable. This proc will resolve symlinks.

See also:

Source Edit 
proc getAppDir(): string {...}{.gcsafe, extern: "nos$1", tags: [ReadIOEffect],
                           raises: [].}

Returns the directory of the application's executable.

See also:

Source Edit 
proc sleep(milsecs: int) {...}{.gcsafe, extern: "nos$1", tags: [TimeEffect],
                           raises: [].}
Sleeps milsecs milliseconds. Source Edit 
proc getFileSize(file: string): BiggestInt {...}{.gcsafe, extern: "nos$1",
    tags: [ReadIOEffect], raises: [IOError, OSError].}
Returns the file size of file (in bytes). OSError is raised in case of an error. Source Edit 
proc getFileInfo(handle: FileHandle): FileInfo {...}{.raises: [OSError], tags: [].}

Retrieves file information for the file object represented by the given handle.

If the information cannot be retrieved, such as when the file handle is invalid, OSError is raised.

See also:

Source Edit 
proc getFileInfo(file: File): FileInfo {...}{.raises: [IOError, OSError], tags: [].}

Retrieves file information for the file object.

See also:

Source Edit 
proc getFileInfo(path: string; followSymlink = true): FileInfo {...}{.
    raises: [OSError], tags: [].}

Retrieves file information for the file object pointed to by path.

Due to intrinsic differences between operating systems, the information contained by the returned FileInfo object will be slightly different across platforms, and in some cases, incomplete or inaccurate.

When followSymlink is true (default), symlinks are followed and the information retrieved is information related to the symlink's target. Otherwise, information on the symlink itself is retrieved.

If the information cannot be retrieved, such as when the path doesn't exist, or when permission restrictions prevent the program from retrieving file information, OSError is raised.

See also:

Source Edit 
proc isHidden(path: string): bool {...}{.raises: [], tags: [].}

Determines whether path is hidden or not, using this reference.

On Windows: returns true if it exists and its "hidden" attribute is set.

On posix: returns true if lastPathPart(path) starts with . and is not . or ...

Note: paths are not normalized to determine isHidden.

Example:

when defined(posix):
  assert ".foo".isHidden
  assert not ".foo/bar".isHidden
  assert not ".".isHidden
  assert not "..".isHidden
  assert not "".isHidden
  assert ".foo/".isHidden
Source Edit 
proc getCurrentProcessId(): int {...}{.raises: [], tags: [].}

Return current process ID.

See also:

Source Edit 
proc setLastModificationTime(file: string; t: times.Time) {...}{.raises: [OSError],
    tags: [].}
Sets the file's last modification time. OSError is raised in case of an error. Source Edit

Funcs

func isValidFilename(filename: string; maxLen = 259.Positive): bool {...}{.
    raises: [], tags: [].}

Returns true if filename is valid for crossplatform use.

This is useful if you want to copy or save files across Windows, Linux, Mac, etc. You can pass full paths as argument too, but func only checks filenames. It uses invalidFilenameChars, invalidFilenames and maxLen to verify the specified filename.

assert not isValidFilename(" foo")    ## Leading white space
assert not isValidFilename("foo ")    ## Trailing white space
assert not isValidFilename("foo.")    ## Ends with Dot
assert not isValidFilename("con.txt") ## "CON" is invalid (Windows)
assert not isValidFilename("OwO:UwU") ## ":" is invalid (Mac)
assert not isValidFilename("aux.bat") ## "AUX" is invalid (Windows)
Source Edit

Iterators

iterator parentDirs(path: string; fromRoot = false; inclusive = true): string {...}{.
    raises: [], tags: [].}

Walks over all parent directories of a given path.

If fromRoot is true (default: false), the traversal will start from the file system root directory. If inclusive is true (default), the original argument will be included in the traversal.

Relative paths won't be expanded by this iterator. Instead, it will traverse only the directories appearing in the relative path.

See also:

Examples:

let g = "a/b/c"

for p in g.parentDirs:
  echo p
# a/b/c
# a/b
# a

for p in g.parentDirs(fromRoot=true):
  echo p
# a/
# a/b/
# a/b/c

for p in g.parentDirs(inclusive=false):
  echo p
# a/b
# a
Source Edit 
iterator envPairs(): tuple[key, value: TaintedString] {...}{.tags: [ReadEnvEffect],
    raises: [].}

Iterate over all environments variables.

In the first component of the tuple is the name of the current variable stored, in the second its value.

See also:

Source Edit 
iterator walkPattern(pattern: string): string {...}{.tags: [ReadDirEffect],
    raises: [].}

Iterate over all the files and directories that match the pattern.

On POSIX this uses the glob call. pattern is OS dependent, but at least the "*.ext" notation is supported.

See also:

Source Edit 
iterator walkFiles(pattern: string): string {...}{.tags: [ReadDirEffect], raises: [].}

Iterate over all the files that match the pattern.

On POSIX this uses the glob call. pattern is OS dependent, but at least the "*.ext" notation is supported.

See also:

Source Edit 
iterator walkDirs(pattern: string): string {...}{.tags: [ReadDirEffect], raises: [].}

Iterate over all the directories that match the pattern.

On POSIX this uses the glob call. pattern is OS dependent, but at least the "*.ext" notation is supported.

See also:

Source Edit 
iterator walkDir(dir: string; relative = false; checkDir = false): tuple[
    kind: PathComponent, path: string] {...}{.tags: [ReadDirEffect],
    raises: [OSError].}

Walks over the directory dir and yields for each directory or file in dir. The component type and full path for each item are returned.

Walking is not recursive. If relative is true (default: false) the resulting path is shortened to be relative to dir. Example: This directory structure:

dirA / dirB / fileB1.txt
     / dirC
     / fileA1.txt
     / fileA2.txt

and this code:

for kind, path in walkDir("dirA"):
  echo(path)

produce this output (but not necessarily in this order!):

dirA/dirB
dirA/dirC
dirA/fileA1.txt
dirA/fileA2.txt

See also:

Source Edit 
iterator walkDirRec(dir: string; yieldFilter = {pcFile}; followFilter = {pcDir};
                    relative = false; checkDir = false): string {...}{.
    tags: [ReadDirEffect], raises: [OSError].}

Recursively walks over the directory dir and yields for each file or directory in dir.

If relative is true (default: false) the resulting path is shortened to be relative to dir, otherwise the full path is returned.

Warning: Modifying the directory structure while the iterator is traversing may result in undefined behavior!

Walking is recursive. followFilter controls the behaviour of the iterator:

yieldFilter meaning
pcFile yield real files (default)
pcLinkToFile yield symbolic links to files
pcDir yield real directories
pcLinkToDir yield symbolic links to directories
followFilter meaning
pcDir follow real directories (default)
pcLinkToDir follow symbolic links to directories

See also:

Source Edit

Templates

template existsFile(args: varargs[untyped]): untyped {...}{.
    deprecated: "use fileExists".}
Deprecated: use fileExists
Source Edit 
template existsDir(args: varargs[untyped]): untyped {...}{.
    deprecated: "use dirExists".}
Deprecated: use dirExists
Source Edit

© 2006–2021 Andreas Rumpf
Licensed under the MIT License.
https://nim-lang.org/docs/os.html