I have this setup file:

function latest { 
    count=${1:-5} ; 
    echo "Just changed"
    ls -lrtd * | tail -$count ; 

I call it:

. setup

Then I ask bash if the latest function is defined:

>type latest
latest is a function
latest () 
    echo "Just changed";
    ls --color=auto -lrtd * | tail -$count

Just changed is an arbitrary string that I used to make sure I was not looking at a definition of latest from another file.

And the question is: why is Bash adding the --color=auto to the ls command (where it is of no use since the output is piped anyway). And yes, on my shell ls is aliased to ls --color=auto, and if I remove the alias this doesn't happen. But I thought aliases where not used in functions and in any case this substitution happened at function definition time?

3 Answers 3


You've observed documented behavior; in the Alias section of the bash manual:

Aliases are expanded when a function definition is read, not when the function is executed, because a function definition is itself a command.


Jeff is correct above. To see the aliases defined in your shell, type "alias" at the prompt.


[USERID ~] $ alias
alias l.='ls -d .* --color=auto'
alias ll='ls -ahlF'
alias ls='ls --color=auto'
alias vi='vim'
[USERID ~] $

To avoid the alias in your script, you would need to either unalias the "ls" command or call it directly. To find the location of "ls", use the type shell builtin:

[USERID ~] $ type -P ls

You could put that in a variable and call "ls" using the variable:

[USERID ~] $ lsCmd=$(type -P ls)
[USERID ~] $ echo $lsCmd
[USERID ~] $ ls
MyAppData  MyDocuments  MyDownloads  Scripts  tmp.VOOlcGffwf  tmp.Y6IE7S2ps4
[USERID ~] $ $lsCmd
MyAppData  MyDocuments  MyDownloads  Scripts  tmp.VOOlcGffwf  tmp.Y6IE7S2ps4

In the first case, calling just "ls" gives the output in color because "ls" is aliased to "ls --color=auto" but the second case give the output without color as the alias is bypassed.


Both older answers are true, they explain why and when Bash expands aliases. But if you wish to get rid of the (annoying) ls-alias rendering some directory listings unreadable with too-alike colours on screen, the definition of the alias to remove is in file /etc/skel/.bashrc

  • 3
    Removing it from /etc/skel doesn't help for existing users, since the files there are only used to populate the home directories of new users. Anyway, setting the colors is a different question
    – ilkkachu
    Mar 27, 2021 at 11:24
  • ilkkachu has got it right, existing users can remove it from their ~/.bashrc -- I'm just so weird I remove it from skeleton after install before populating :-) It's just so wrong to override basic commands to same name.
    – Seikku
    Mar 28, 2021 at 1:35

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