Difference between 'dir' and 'ls' terminal commands?
Solution 1
dir
and ls
are part of coreutils
and dir
is almost the same as ls
, just with different default options.
The GNU Core Utilities are the basic file, shell and text manipulation utilities of the GNU operating system. These are the core utilities which are expected to exist on every operating system.
info dir
says:
dir
is equivalent tols -C -b
; that is, by default files are listed in columns, sorted vertically, and special characters are represented by backslash escape sequences.
Oh and there is also vdir
! info vdir
says:
vdir
is equivalent tols -l -b
; that is, by default files are listed in long format and special characters are represented by backslash escape sequences.
Most likely dir
exists for backwards compatibility or due to historical reasons.
Solution 2
The Relationship Between ls
and dir
ls
and dir
are separate programs that behave similarly. As explained and referenced below, the purpose of dir
is to provide a command like ls
whose output does not vary depending on whether or not it is going to a terminal. To achieve this helpfully, dir
must format its output in a way that is reasonable and useful both for viewing in a terminal and for writing to a file or pipe.
There are two common misconceptions about dir
:
- Many people believe
dir
is an alias ofls
, but that is not the case. Neither command is an alias of the other, and by default in Ubuntu,dir
is not an alias at all.ls
anddir
are provided by separate, non-identical executables. - Many people believe
dir
exists for obscure historical reasons or to provide compatibility with some standard or some other OS. That is not the case either.ls
behaves the way it does for compatibilty.dir
, which doesn't have to be compatible because it's not a standard Unix command, behaves in an alternate way that the developers consider valuable in its own right and possibly even preferable.
OK, but exactly how do ls
and dir
differ?
Both ls
and dir
list the contents of directories. Two specific differences in their default behaviors distinguish them.
-
When its standard output is a terminal,
ls
lists filenames in vertically sorted columns (likels -C
). When its standard output is not a terminal (for example, a file or pipe),ls
lists filenames one per line (likels -1
).Whether or not its standard output is a terminal,
dir
lists filenames in vertically sorted columns (likels -C
).For both
ls
anddir
, these defaults may be overridden by the--format=
flag and by the-1
,-C
,-m
, and-x
flags, which abbreviate particular--format=
options. See 10.1.4 General output formatting in the GNU coreutils reference manual for details. -
When its standard output is a terminal and a filename to be listed contains control characters,
ls
prints?
instead of each control character (likels -q
). When its standard output is not a terminal,ls
prints control characters as-is (likels --show-control-chars
).Whether or not its standard output is a terminal, when
dir
encounters a control character or any other character that would be interpreted specially if entered into a shell, it prints backslash sequences for the characters. This includes even relatively common characters like spaces. For example,dir
will list an entry calledDocuments backups
asDocuments\ backups
. This is likels -b
.For both
ls
anddir
, these defaults may be overridden by the flags listed in 10.1.7 Formatting the file names in the GNU coreutils reference manual. This includes-b
,-q
,--quoting-style=
, and some others.
Sources: ls invocation and dir invocation, in the GNU coreutils reference manual.
Why have dir
?
The rationale for a separate dir
utility is given in 4.5 Standards for Interfaces Generally of the GNU coding standards. I recommend reading that whole section to understand the developers' reasoning, but here are the highlights as applicable to ls
/dir
:
Please don’t make the behavior of a utility depend on the name used to invoke it....
Instead, use a run time option or a compilation switch or both to select among the alternate behaviors....
Likewise, please don’t make the behavior of a command-line program depend on the type of output device....
Compatibility requires certain programs to depend on the type of output device. It would be disastrous if
ls
orsh
did not do so in the way all users expect. In some of these cases, we supplement the program with a preferred alternate version that does not depend on the output device type. For example, we provide adir
program much likels
except that its default output format is always multi-column format.
The GNU Project considers it undesirable, from a technical perspective, for a utility to produce different output depending on what kind of device it is writing to (at least in the utility's default configuration). For some utilities, including ls
, device-dependent output is necessary for compatibility and so it works the way users expect. Some users do also specifically prefer this device-dependent behavior.
While ls
could not reasonably be written to behave device independently, a separate dir
utility was created to achieve this. Thus dir
is not the utility that behaves strangely for reasons of historical compatibility--ls
is.
To see how ls
, dir
, and the related vdir
utility are implemented in the coreutils source code without needless code duplication, see ls-dir.c
, ls-ls.c
, ls-vdir.c
, ls.h
, and ls.c
.
Is dir
really useful?
If you've ever wished ls
produced multi-column output even when you piped it to less
(ls | less
) or redirected it to a file (ls > out.txt
), you can use dir
or ls -C
.
If you've ever wished you could directly copy a filename shown by ls
and use it as part of a command without worrying about quoting, you can use dir
or ls -b
.
dir
is equivalent to ls -Cb
, so in that sense you don't need dir
. But dir
provides a combination of options that in practice is often useful (though not widely known about).
Why do I get colorized output from ls
(even ls -Cb
) but not dir
?!
Most Ubuntu users have an alias called ls
which runs ls --color=auto
. When ls
exists both as an alias and an external command, the alias takes precedence in simple, interactive commands.
Alias definitions aren't expanded recursively--it's the external ls
command that the ls
alias is calling with --color=auto
. See 6.6 Aliases in the Bash reference manual for more information on how aliases work.
When passed to ls
, dir
, or vdir
(and some other commands, like grep
), --color=auto
uses color when its output is a terminal, but not otherwise.
By default in Ubuntu, user accounts are created with this in ~/.bashrc
:
# enable color support of ls and also add handy aliases
if [ -x /usr/bin/dircolors ]; then
test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
alias ls='ls --color=auto'
#alias dir='dir --color=auto'
#alias vdir='vdir --color=auto'
alias grep='grep --color=auto'
alias fgrep='fgrep --color=auto'
alias egrep='egrep --color=auto'
fi
You'll notice the ls
alias (alias ls='ls --color=auto'
) is uncommented, while those for dir
and vdir
are commented out with #
so they take no effect. That is, while dir
is not an alias, ls
is (but not to dir
).
How do I make dir
produce colored output, too?
To enable colored output with dir
, simply edit .bashrc
in your home directory and uncomment the #alias dir='dir --color=auto'
line by removing the leading #
. In shells started after the change, dir
will be an alias.
If you want the change in the current shell, you can run the alias definition as a command, or you can source .bashrc
by running . ~/.bashrc
.
This arguably goes against the main point of dir
--that it should produce the same sort of output regardless of the output device. However:
- If you find it useful to make this
dir
alias, you should certainly do so. - When called as an external command, for example in scripts or if you override the alias by running
\dir
orcommand dir
,dir
will still produce device-independent output. This is to say that aliasingdir
todir --color=auto
does not really breakdir
.
Solution 3
I would be inclined to think that
dir
is there just for backwards compatibility.From GNU Coreutils:
dir is equivalent to ls -C -b; that is, by default files are listed in columns, sorted vertically, and special characters are represented by backslash escape sequences.
By the way,
ls
doesn't colorize the output by default: this is because most distros aliasls
tols --color=auto
in/etc/profile.d
. For a test, typeunalias ls
then tryls
: it will be colorless.
Source: Renan's answer to What's the difference between “dir” and “ls”?
Solution 4
When in doubt, compare type ls
vs type dir
(see also Difference between ls and la):
$ type dir
dir is aliased to `ls -l'
$ type ls
ls is aliased to `_ls'
$ type _ls
_ls is a function
_ls ()
{
local IFS=' ';
command ls $LS_OPTIONS ${1+"$@"}
}
$ echo command ls $LS_OPTIONS ${1+"$@"}
command ls -N --color=tty -T 0
The difference boils down to different options to ls
, in my case --color=tty
would be the most visible, your system may differ.
Solution 5
Short Answer : None,
dir
is the same source code than ls
, ls
binary have --color
by default. (1 line of code diff)
Related videos on Youtube
BretD
Updated on September 18, 2022Comments
-
BretD almost 2 years
I've been trying to find the difference between using the
dir
andls
commands in terminal. I knowls
is the traditional UNIX method of viewing the files in a directory, and thatdir
is the windows command prompt equivalent, but both commands work in terminal.If I type in
dir
, it displays the files and folders in the directory, and if I typels
, it does the same, except with content highlighting. Both commands accept options (i.e.ls -a
anddir -a
both return all files and folders and hidden files.So does anyone know what the difference is and why both
dir
andls
are used?-
Rinzwind over 12 years
dir --color
;) -
BretD over 12 yearsjust wanted to say I'm surprised at the amount of response this question has received. I guess I was not the only one wondering about this :)
-
Rinzwind over 12 yearsCommands from ancient times always drag the older nerds out of the woodwork ;)
-
-
Dom over 12 yearstype
alias dir
to see what it actually is. typealias
to see all aliases. -
James over 12 years@user606723 , 'alias dir' doesn't show in 11.10 (at least not for me). I believe 'alias' only shows local user alias settings, not system wide.
-
Francisco Valdez about 12 yearsYes, I agree with you, but in this case, is not similar source code, is the same source code. If we say that an alias is just anything listed in
alias
then of course is not an alias. -
Eliah Kagan about 12 yearsIt is not the same source code. As you said, "one line of source is changed." And if it were the same source then it would still not be an alias. There are lots of things in a Unix-like system that are similar to aliases but which would be vastly confusing to novices (and exasperating to experienced users) to call aliases. Symbolic links, hard links, identical files, similar files, wrapper scripts, shell builtins hiding executables, and synced files (e.g. with UbuntuOne) are all similar to aliases in significant ways, but they aren't aliases.
-
Kevin over 7 yearsQuality answer, but could use a ToC or TL;DR; :)
-
Eliah Kagan over 7 yearsThis doesn't seem like a default Ubuntu user configuration at all. I don't think any of the Ubuntu systems I've used have have had
ls
as an alias for a function called_ls
-- not even as a commented-out line in.bashrc
. It does seem like the default for (at least some versions of) openSuSE, though, judging by this conversation, this file (linked from there), and my (admittedly perhaps wrong) memory of when I last used openSUSE. -
user2394284 over 7 years@EliahKagan: You guessed it, I'm using OpenSuse! So as I said, the result will differ, but the method should be all right.
-
ychaouche over 7 yearstype
type dir
to see what it is (an alias, a command, a bash function...) -
Eliah Kagan over 6 yearsAlthough
dir
is not provided for backwards compatibility--andls
actually is--this answer (and the answer it quotes from) does correctly state the technical difference between the two commands as well as explaining the commonly observed colorization difference. So +1.