File size
You are encouraged to solve this task according to the task description, using any language you may know.
In this task, the job is to verify the size of a file called "input.txt" for a file in the current working directory and another one in the file system root.
Ada
<lang ada>with Ada.Directories; use Ada.Directories; with Ada.Text_IO; use Ada.Text_IO;
procedure Test_File_Size is begin
Put_Line (File_Size'Image (Size ("input.txt")) & " bytes"); Put_Line (File_Size'Image (Size ("/input.txt")) & " bytes");
end Test_File_Size;</lang> Note that reference to the root directory, if there is any, is OS specific.
ALGOL 68
There is no build in way to find the size of an arbitrary file, especially of the file is a special channel, e.g. a tape device.
Conceptually the procedure <lang algol68>PROC set = (REF FILE file, INT page, line, character)VOID: ~ </lang> could be used to do a binary search find the last page's page number. And if it is known that every page has the same number of lines, and every line has the same number of char[s], and the character set is not compressible, then the size could be quickly calculated. Otherwise every page, and every line would have to be tallied.
It is probably much easier to use some an operating system library. This library is not part of the standard ALGOL 68 language definition.
AutoHotkey
<lang AutoHotkey>FileGetSize, FileSize, input.txt ; Retrieve the size in bytes. MsgBox, Size of input.txt is %FileSize% bytes FileGetSize, FileSize, \input.txt, K ; Retrieve the size in Kbytes. MsgBox, Size of \input.txt is %FileSize% Kbytes</lang>
BBC BASIC
<lang bbcbasic> file% = OPENIN(@dir$+"input.txt")
IF file% THEN PRINT "File size = " ; EXT#file% CLOSE #file% ENDIF file% = OPENIN("\input.txt") IF file% THEN PRINT "File size = " ; EXT#file% CLOSE #file% ENDIF</lang>
Bracmat
This solution assumes that the file can be opened for reading. The fil
function is the Bracmat interface to the underlying C functions fopen, fclose, fseek, ftell, fread, fgetc, fwrite, fputc
and feof
. More than one file can be opened at the same time. Focus is shifted from one open file to another by mentioning the file name as the first argument.
<lang bracmat>(getFileSize=
size
. fil$(!arg,rb) {read in binary mode}
& fil$(,END) {seek to end of file} & fil$(,TEL):?size {tell where we are} & fil$(,SET,-1) {seeking to an impossible position closes the file, and fails} | !size {return the size}
);
getFileSize$"valid.bra" 113622
getFileSize$"c:\\boot.ini" 211 </lang>
C
<lang c>#include <stdlib.h>
- include <stdio.h>
long getFileSize(const char *filename) {
long result; FILE *fh = fopen(filename, "rb"); fseek(fh, 0, SEEK_END); result = ftell(fh); fclose(fh); return result;
}
int main(void) {
printf("%ld\n", getFileSize("input.txt")); printf("%ld\n", getFileSize("/input.txt")); return 0;
}</lang>
<lang c>#include <stdlib.h>
- include <stdio.h>
- include <sys/stat.h>
int main(void) {
struct stat foo; stat("input.txt", &foo); printf("%ld\n", foo.st_size); stat("/input.txt", &foo); printf("%ld\n", foo.st_size); return 0;
}</lang>
C++
<lang cpp>#include <iostream>
- include <fstream>
std::ios::off_type getFileSize(const char *filename) {
std::ifstream f(filename); std::ios::pos_type begin = f.tellg(); f.seekg(0, std::ios::end); std::ios::pos_type end = f.tellg(); return end - begin;
}
int main() {
std::cout << getFileSize("input.txt") << std::endl; std::cout << getFileSize("/input.txt") << std::endl; return 0;
}</lang>
C#
<lang csharp>using System; using System.IO;
class Program {
static void Main(string[] args) { Console.WriteLine(new FileInfo("/input.txt").Length); Console.WriteLine(new FileInfo("input.txt").Length); }
} </lang>
Clean
There is not function to get the file size, therefore we seek to the end and query the file pointer position.
<lang clean>import StdEnv
fileSize fileName world
# (ok, file, world) = fopen fileName FReadData world | not ok = abort "Cannot open file" # (ok, file) = fseek file 0 FSeekEnd | not ok = abort "Cannot seek file" # (size, file) = fposition file (_, world) = fclose file world = (size, world)
Start world = fileSize "input.txt" world</lang>
Clojure
<lang clojure>(import '[java.io File]) (defn show-size [filename]
(println filename "size:" (.length (File. filename))))
(show-size "input.txt") (show-size "/input.txt")</lang>
ColdFusion
<lang ColdFusion><cfscript>
localFile = getFileInfo(expandpath("input.txt")); rootFile = getFileInfo("/input.txt");
</cfscript>
<cfoutput>
Size of input.txt is #localFile.size# bytes. Size of /input.txt is #rootFile.size# bytes.
</cfoutput></lang>
Common Lisp
<lang lisp>(with-open-file (stream (make-pathname :name "input.txt")
:direction :input :if-does-not-exist nil) (print (if stream (file-length stream) 0)))
(with-open-file (stream (make-pathname :directory '(:absolute "") :name "input.txt")
:direction :input :if-does-not-exist nil) (print (if stream (file-length stream) 0)))</lang>
D
<lang d>import std.file, std.stdio, std.path, std.file, std.stream,
std.mmfile;
void main() {
immutable fileName = "file_size.exe";
try { writefln("File '%s' has size:", fileName);
writefln("%10d bytes by std.file.getSize (function)", std.file.getSize(fileName));
writefln("%10d bytes by std.stream (class)", new std.stream.File(fileName).size);
// mmfile can treat the file as an array in memory. writefln("%10d bytes by std.mmfile (class)", new std.mmfile.MmFile(fileName).length); } catch (Exception e) { e.msg.writefln; }
}</lang>
- Output:
File 'file_size.exe' has size: 1066164 bytes by std.file.getSize (function) 1066164 bytes by std.stream (class) 1066164 bytes by std.mmfile (class)
Delphi
<lang Delphi>program SizeOfFile;
{$APPTYPE CONSOLE}
uses SysUtils;
function CheckFileSize(const aFilename: string): Integer; var
lFile: file of Byte;
begin
AssignFile(lFile, aFilename); FileMode := 0; {Access file in read only mode} Reset(lFile); Result := FileSize(lFile); CloseFile(lFile);
end;
begin
Writeln('input.txt ', CheckFileSize('input.txt')); Writeln('\input.txt ', CheckFileSize('\input.txt'));
end.</lang>
E
<lang e>for file in [<file:input.txt>, <file:///input.txt>] {
println(`The size of $file is ${file.length()} bytes.`)
}</lang>
Eiffel
<lang eiffel> class
APPLICATION
create
make
feature {NONE} -- Initialization
make -- Run application. do create input_file.make_open_read ("input.txt") print(input_file.count) print("%N") input_file.close create environment input_file.make_open_read(environment.root_directory_name + "input.txt") print(input_file.count) input_file.close end
feature -- Access
input_file: PLAIN_TEXT_FILE environment:EXECUTION_ENVIRONMENT
end </lang>
Emacs Lisp
This shows nil
if no such file since
file-attributes
returns nil
in that case.
<lang Lisp>(message "sizes are %s and %s"
(nth 7 (file-attributes "input.txt")) (nth 7 (file-attributes "/input.txt")))</lang>
Erlang
<lang erlang>-module(file_size). -export([file_size/0]).
-include_lib("kernel/include/file.hrl").
file_size() ->
print_file_size("input.txt"), print_file_size("/input.txt").
print_file_size(Filename) ->
case file:read_file_info(Filename) of
{ok, FileInfo} -> io:format("~s ~p~n", [Filename, FileInfo#file_info.size]); {error, _} -> io:format("~s could not be opened~n",[Filename])
end.
</lang>
Euphoria
<lang euphoria>include file.e
function file_size(sequence file_name)
object x x = dir(file_name) if sequence(x) and length(x) = 1 then return x[1][D_SIZE] else return -1 -- the file does not exist end if
end function
procedure test(sequence file_name)
integer size size = file_size(file_name) if size < 0 then printf(1,"%s file does not exist.\n",{file_name}) else printf(1,"%s size is %d.\n",{file_name,size}) end if
end procedure
test("input.txt") -- in the current working directory test("/input.txt") -- in the file system root</lang>
Factor
<lang factor>"input.txt" file-info size>> .
1321
"file-does-not-exist.txt" file-info size>>
"Unix system call ``stat failed:"...</lang>
FBSL
FileLen returns -1 if the file is not found. FileLen will also accept a file handle and give the file length of the open file. <lang qbasic>#APPTYPE CONSOLE
print FileLen("sync.log") print FileLen("\sync.log") PAUSE </lang>
Forth
<lang forth>: .filesize ( addr len -- ) 2dup type ." is "
r/o open-file throw dup file-size throw <# #s #> type ." bytes long." cr close-file throw ;
s" input.txt" .filesize
s" /input.txt" .filesize</lang>
F#
<lang fsharp>open NUnit.Framework open FsUnit
[<Test>] let ``Validate that the size of the two files is the same`` () =
let local = System.IO.FileInfo(__SOURCE_DIRECTORY__ + "\input.txt") let root = System.IO.FileInfo(System.IO.Directory.GetDirectoryRoot(__SOURCE_DIRECTORY__) + "input.txt") local.Length = root.Length |> should be True</lang>
Go
<lang go>package main
import "fmt" import "os"
func printFileSize(f string) {
if stat, err := os.Stat(f); err != nil { fmt.Println(err) } else { fmt.Println(stat.Size()) }
}
func main() {
printFileSize("input.txt") printFileSize("/input.txt")
}</lang>
Groovy
<lang groovy>println new File('index.txt').length(); println new File('/index.txt').length();</lang>
Haskell
<lang haskell>import System.IO
printFileSize filename = withFile filename ReadMode hFileSize >>= print
main = mapM_ printFileSize ["input.txt", "/input.txt"]</lang> or <lang haskell>import System.Posix.File
printFileSize filename = do stat <- getFileStatus filename
print (fileSize stat)
main = mapM_ printFileSize ["input.txt", "/input.txt"]</lang>
HicEst
<lang hicest>READ(FILE="input.txt", LENgth=bytes) ! bytes = -1 if not existent READ(FILE="C:\input.txt", LENgth=bytes) ! bytes = -1 if not existent </lang>
Icon and Unicon
Icon doesn't support 'stat'; however, information can be obtained by use of the system function to access command line. <lang Unicon>every dir := !["./","/"] do {
write("Size of ",f := dir || "input.txt"," = ",stat(f).size) |stop("failure for to stat ",f) }</lang>
Note: Icon and Unicon accept both / and \ for directory separators.
J
<lang J>require 'files' fsize 'input.txt';'/input.txt'</lang>
Java
<lang java>import java.io.File;
public class FileSize {
public static void main ( String[] args ) { System.out.println("input.txt : " + new File("input.txt").length() + " bytes"); System.out.println("/input.txt : " + new File("/input.txt").length() + " bytes"); }
} </lang>
JavaScript
<lang javascript>var fso = new ActiveXObject("Scripting.FileSystemObject"); fso.GetFile('input.txt').Size; fso.GetFile('c:/input.txt').Size;</lang>
The following works in all browsers, including IE10. <lang javascript>var file = document.getElementById("fileInput").files.item(0); //a file input element if (file) { var reader = new FileReader(); reader.readAsText(file, "UTF-8"); reader.onload = loadedFile; reader.onerror = errorHandler; } function loadedFile(event) { var fileString = event.target.result; alert(fileString.length); } function errorHandler(event) { alert(event); }</lang>
K
<lang K>_size "input.txt" _size "/input.txt"</lang>
Lasso
<lang Lasso>// local to current directory local(f = file('input.txt')) handle => { #f->close }
- f->size
// file at file system root local(f = file('//input.txt')) handle => { #f->close }
- f->size
</lang>
Liberty BASIC
<lang lb>'input.txt in current directory OPEN DefaultDir$ + "/input.txt" FOR input AS #m PRINT "File size: "; lof(#m) CLOSE #m
'input.txt in root OPEN "c:/input.txt" FOR input AS #m PRINT "File size: "; lof(#m) CLOSE #m</lang>
Lua
<lang Lua>function GetFileSize( filename )
local fp = io.open( filename ) if fp == nil then return nil end local filesize = fp:seek( "end" ) fp:close() return filesize
end</lang>
Mathematica
<lang Mathematica> FileByteCount["input.txt"] FileByteCount[FileNameJoin[{$RootDirectory, "input.txt"}]]</lang>
MATLAB / Octave
<lang matlab>d1 = dir('input.txt'); d2 = dir('/input.txt'); fprintf('Size of input.txt is %d bytes\n', d1.bytes) fprintf('Size of /input.txt is %d bytes\n', d2.bytes)</lang>
MAXScript
<lang maxscript>-- Returns filesize in bytes or 0 if the file is missing getFileSize "index.txt" getFileSize "\index.txt"</lang>
Mirah
<lang mirah>import java.io.File
puts File.new('file-size.mirah').length() puts File.new("./#{File.separator}file-size.mirah").length()</lang>
mIRC Scripting Language
<lang mirc>echo -ag $file(input.txt).size bytes echo -ag $file(C:\input.txt).size bytes</lang>
Modula-3
<lang modula3>MODULE FSize EXPORTS Main;
IMPORT IO, Fmt, FS, File, OSError;
VAR fstat: File.Status;
BEGIN
TRY fstat := FS.Status("input.txt"); IO.Put("Size of input.txt: " & Fmt.LongInt(fstat.size) & "\n"); fstat := FS.Status("/input.txt"); IO.Put("Size of /input.txt: " & Fmt.LongInt(fstat.size) & "\n"); EXCEPT | OSError.E => IO.Put("ERROR: Could not get file status.\n"); END;
END FSize.</lang>
NetRexx
<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols binary
runSample(arg) return
-- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . method fileSize(fn) public static returns double
ff = File(fn) fSize = ff.length() return fSize
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ method runSample(arg) private static
parse arg files if files = then files = 'input.txt F docs D /input.txt F /docs D' loop while files.length > 0 parse files fn ft files select case(ft.upper()) when 'F' then do ft = 'File' end when 'D' then do ft = 'Directory' end otherwise do ft = 'File' end end sz = fileSize(fn) say ft 'fn' sz 'bytes.' end
return
</lang>
Objective-C
<lang objc>NSFileManager *fm = [NSFileManager defaultManager];
// Pre-OS X 10.5 NSLog(@"%llu", [[fm fileAttributesAtPath:@"input.txt" traverseLink:YES] fileSize]);
// OS X 10.5+ NSLog(@"%llu", [[fm attributesOfItemAtPath:@"input.txt" error:NULL] fileSize]);</lang>
Objeck
<lang objeck> use IO; ... File("input.txt")->Size()->PrintLine(); File("c:\input.txt")->Size()->PrintLine(); </lang>
OCaml
<lang ocaml>let printFileSize filename =
let ic = open_in filename in Printf.printf "%d\n" (in_channel_length ic); close_in ic ;;
printFileSize "input.txt" ;; printFileSize "/input.txt" ;;</lang>
For files greater than Pervasives.max_int, one can use the module Unix.LargeFile: <lang ocaml>let printLargeFileSize filename =
let ic = open_in filename in Printf.printf "%Ld\n" (LargeFile.in_channel_length ic); close_in ic ;;</lang>
Alternatively: <lang ocaml>#load "unix.cma" ;; open Unix ;; Printf.printf "%d\n" (stat "input.txt").st_size ;; Printf.printf "%d\n" (stat "/input.txt").st_size ;;</lang>
Oz
<lang oz>declare
[Path] = {Module.link ['x-oz://system/os/Path.ozf']}
in
{Show {Path.size "input.txt"}} {Show {Path.size "/input.txt"}}</lang>
Pascal
See Delphi
Perl
<lang perl>use File::Spec::Functions qw(catfile rootdir); print -s 'input.txt'; print -s catfile rootdir, 'input.txt';</lang>
Perl 6
<lang perl6>say 'input.txt'.IO.s; say '/input.txt'.IO.s;</lang>
PHP
<lang php><?php echo filesize('input.txt'), "\n"; echo filesize('/input.txt'), "\n"; ?></lang>
PicoLisp
<lang PicoLisp>(println (car (info "input.txt"))) (println (car (info "/input.txt")))</lang>
Pike
<lang pike>import Stdio;
int main(){
write(file_size("input.txt") + "\n"); write(file_size("/input.txt") + "\n");
}</lang>
PL/I
<lang PL/I> /* To obtain file size of files in root as well as from current directory. */
test: proc options (main);
declare ch character (1); declare i fixed binary (31); declare in1 file record;
/* Open a file in the root directory. */ open file (in1) title ('//asd.log,type(fixed),recsize(1)'); on endfile (in1) go to next1; do i = 0 by 1; read file (in1) into (ch); end;
next1:
put skip list ('file size in root directory =' || trim(i)); close file (in1);
/* Open a file in the current dorectory. */ open file (in1) title ('/asd.txt,type(fixed),recsize(1)'); on endfile (in1) go to next2; do i = 0 by 1; read file (in1) into (ch); end;
next2:
put skip list ('local file size=' || trim(i));
end test; </lang>
I used differently-named files to prove that local and root directory files were accessed. This program ran with Windows PL/I.
Pop11
<lang pop11>;;; prints file size in bytes sysfilesize('input.txt') => sysfilesize('/input.txt') =></lang>
PostScript
status
returns status information about a file if given a file name. This includes the size in pages (implementation-dependent), the size in bytes, creation and modification time and a final true
. The values not needed here are simply pop
ed off the stack.
<lang postscript>(input.txt ) print
(input.txt) status pop pop pop = pop
(/input.txt ) print
(/input.txt) status pop pop pop = pop</lang>
PowerShell
<lang powershell>Get-ChildItem input.txt | Select-Object Name,Length Get-ChildItem \input.txt | Select-Object Name,Length</lang>
PureBasic
<lang purebasic>Debug FileSize("input.txt") Debug FileSize("/input.txt")</lang>
Python
<lang python>import os
size = os.path.getsize('input.txt') size = os.path.getsize('/input.txt')</lang>
R
R has a function file.info() in the base package that performs this function. Note that regardless of the OS, R uses forward slashes for the directories.
<lang R>sizeinwd <- file.info('input.txt')"size" sizeinroot <- file.info('/input.txt')"size"</lang>
Racket
<lang Racket>#lang racket (file-size "input.txt") (file-size "/input.txt")</lang>
REBOL
<lang REBOL>size? %info.txt size? %/info.txt size? ftp://username:password@ftp.site.com/info.txt size? http://rosettacode.org</lang>
RapidQ
File I/O is one of the things where RapidQ differs from standard Basic. RapidQ uses file streams.
Method 1: display file size using file streams
<lang rapidq>$INCLUDE "rapidq.inc"
DIM file AS QFileStream
FUNCTION fileSize(name$) AS Integer
file.Open(name$, fmOpenRead) Result = file.Size file.Close
END FUNCTION
PRINT "Size of input.txt is "; fileSize("input.txt") PRINT "Size of \input.txt is "; fileSize("\input.txt")</lang>
Method 2: using DIR$
<lang rapidq>FileName$ = DIR$("input.txt", 0) PRINT "Size of input.txt is "; FileRec.Size FileName$ = DIR$("\input.txt", 0) PRINT "Size of \input.txt is "; FileRec.Size</lang>
Raven
<lang raven>'input.txt' status.size '/input.txt' status.size</lang>
Retro
The simple way is to open and read the size. This may crash if the file does not exist.
<lang Retro>with files' "input.txt" :R open &size sip close drop putn "/input.txt" :R open &size sip close drop putn</lang>
For added stability, check that the returned file handle is not zero:
<lang Retro>with files' "input.txt" :R open over 0 <> [ &size sip close drop ] ifTrue</lang>
Or, if you need to do this more often, setup a function that'll also display an error message if the file does not exist:
<lang Retro>with files'
- getFileSize ( $-n )
:R open 0 over = [ "File does Not Exist\n" puts ] [ &size sip close drop ] if ;
"input.txt" getFileSize putn "/input.txt" getFileSize putn</lang>
REXX
MS DOS version
This REXX example was executed on a Windows/XP system (in a DOS window).
Note that some operating systems don't have a concept of a current directory or a file system root.
<lang rexx>/*REXX pgm to verify a file's size (by reading the lines) in CD & root. */
parse arg iFID . /*let user specify the file ID. */
if iFID== then iFID="FILESIZ.DAT" /*Not specified? Then use default*/
say 'size of' iFID "=" filesize(iFID) 'bytes' /*current dir.*/
say 'size of \..\'iFID "=" filesize('\..\'iFID) 'bytes' /* root dir.*/
exit /*stick a fork in it, we're done.*/
/*──────────────────────────────────FILESIZE subroutine─────────────────*/ filesize: parse arg f; $=0; do while lines(f)\==0
$=$+length(charin(f,,1e6)) end /*while*/
return $</lang> output when using the default input:
size of FILESIZ.DAT = 2 bytes size of \..\FILESIZ.DAT = 5 bytes
CMS version
Note that CMS hasn't a concept of a root.
Also note that the CMS system doesn't normally support the use of periods (.); it uses blanks instead.
<lang rexx>/*REXX pgm to verify a file's size (by reading the lines) on default MD.*/
parse arg iFID /*let user specify the file ID. */
if iFID= then iFID="FILESIZ DAT A" /*Not specified? Then use default*/
say 'size of' iFID "=" filesize(iFID) 'bytes' /*on the default MD.*/
exit /*stick a fork in it, we're done.*/
/*──────────────────────────────────FILESIZE subroutine─────────────────*/ filesize: parse arg f; $=0; do while lines(f)\==0
$=$+length(linein(f)) end /*while*/
return $</lang>
Ruby
<lang ruby>size = File.size('input.txt') size = File.size('/input.txt')</lang>
Run BASIC
<lang runbasic>print fileSize(DefaultDir$,"input.txt") ' current default directory print fileSize("","input.txt") ' root directory
function fileSize(dir$,file$) open dir$;"\";file$ FOR input as #f fileSize = lof(#f) ' Length Of File close #f end function</lang>
Scheme
<lang scheme> (define (file-size filename)
(call-with-input-file filename (lambda (port) (let loop ((c (read-char port)) (count 0)) (if (eof-object? c) count (loop (read-char port) (+ 1 count)))))))
(file-size "input.txt") (file-size "/input.txt") </lang>
Seed7
<lang seed7>$ include "seed7_05.s7i";
const proc: main is func
begin writeln(fileSize("input.txt")); writeln(fileSize("/input.txt")); end func;</lang>
Slate
<lang slate>(File newNamed: 'input.txt') fileInfo fileSize. (File newNamed: '/input.txt') fileInfo fileSize.</lang>
Smalltalk
<lang smalltalk>(File name: 'input.txt') size printNl. (File name: '/input.txt') size printNl.</lang>
<lang smalltalk>'input.txt' asFilename fileSize '/input.txt' asFilename fileSize</lang>
Standard ML
<lang sml>val size = OS.FileSys.fileSize "input.txt" ;; val size = OS.FileSys.fileSize "/input.txt" ;</lang>
Tcl
<lang tcl>file size input.txt file size /input.txt</lang>
Toka
A trivial method follows:
<lang toka>" input.txt" "R" file.open dup file.size . file.close " /input.txt" "R" file.open dup file.size . file.close</lang>
A better method would be to define a new function that actually checks whether the file exists:
<lang toka>[ "R" file.open
dup 0 <> [ dup file.size . file.close ] ifTrue drop
] is display-size
" input.txt" display-size " /input.txt" display-size</lang>
TorqueScript
--Ipquarx June 19th, 10:00 AM
Since TorqueScript cannot set the current working directory, the second part of the task cannot be completed.
TGE Version (Works with all versions containing the basic file i/o):
<lang Torque>%File = new FileObject(); %File.openForRead("input.txt");
while(!%File.isEOF()) { %Length += strLen(%File.readLine()); }
%File.close();
%File.delete();</lang>
T3D Version (Only works with T3D):
<lang Torque>fileSize("input.txt");</lang>
TUSCRIPT
<lang tuscript> $$ MODE TUSCRIPT -- size of file input.txt file="input.txt" ERROR/STOP OPEN (file,READ,-std-) file_size=BYTES ("input.txt") ERROR/STOP CLOSE (file)
-- size of file x:/input.txt ERROR/STOP OPEN (file,READ,x) file_size=BYTES (file) ERROR/STOP CLOSE (file) </lang>
UNIX Shell
An interactive user would run ls -l input.txt /input.txt to see the file sizes. This task is more difficult for a shell script, that must extract each size from command output.
Using ls
ls most likely gets the length from the file's inode.
<lang bash>size1=$(ls -l input.txt | tr -s ' ' | cut -d ' ' -f 5) size2=$(ls -l /input.txt | tr -s ' ' | cut -d ' ' -f 5)</lang>
ls -l reports the size in 5th field, with spaces between fields. tr squeezes spaces (because cut needs one single space between fields), and cut extracts 5th field.
Using wc
wc may actually read the whole file and count the bytes. Some implementations, like wc.c from GNU coreutils, can optimize wc -c by getting the length from the file's inode.
<lang bash>size1=$(wc -c < input.txt | tr -d ' ') size2=$(wc -c < /input.txt | tr -d ' ')</lang>
The peculiar use of wc -c < file, not wc -c file, is to prevent printing the file's name. Then wc only reports the size. Some versions of wc print spaces before the number; tr deletes all these spaces.
Using BSD stat
BSD has stat(1), a nonstandard command. With stat, a shell script can easily get the file size.
<lang bash>size1=$(stat -f %z input.txt) size2=$(stat -f %z /input.txt)</lang>
Z Shell
<lang bash># from module 'zsh/stat', load builtin 'zstat' zmodload -F zsh/stat b:zstat
size1=$(zstat +size input.txt) size2=$(zstat +size /input.txt)</lang>
Vedit macro language
<lang vedit>Num_Type(File_Size("input.txt")) Num_Type(File_Size("/input.txt"))</lang>
Visual Basic .NET
Platform: .NET
<lang vbnet>Dim local As New IO.FileInfo("input.txt") Console.WriteLine(local.Length)
Dim root As New IO.FileInfo("\input.txt") Console.WriteLine(root.Length)</lang>
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