Take the 2-minute tour ×
Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems.. It's 100% free, no registration required.

I have a few aliases in .bash_aliases. I defined c alias as follows, but it does not work as it should:

...
alias cd='cd; ls -r --time=atime'
alias c='cd'
...

In .bashrc there is a line:

alias ls='clear; ls --color=auto'

Commnand c gives bad output now. It should give the same output as cd; clear; ls -r --time=atime --color=auto.

Other problem: When I type cd dir I should stay in dir but I'm in $HOME as a result.

How can I solve this and improve in defining aliases? Is .bash_aliases interpreted as a regular grammar?

share|improve this question
    
Define "bad output". What does it do, and what did you expect it to do? –  cjm Sep 1 '11 at 16:21
    
see question edit. –  xralf Sep 1 '11 at 16:37

2 Answers 2

up vote 9 down vote accepted

Use functions instead, the advantage being the possibility to pass parameters and a cleaner syntax.

function cd() {
  command cd "$@"
  ls -r --time=atime
}

function c() {
 cd "$@"
}

function ls() {
  clear
  command ls --color=auto "$@"
}

(command is a bash builtin used to refer to the real command, and not functions with the same name).

share|improve this answer
    
command cd will give you command not found: cd, you meant builtin cd. –  Stéphane Gimenez Sep 1 '11 at 16:44
    
@Stéphane Gimenez: are you sure? it works here –  enzotib Sep 1 '11 at 16:46
    
Seems that bash strangely accepts it. zsh doesn't… and dash don't know about builtin… what a mess. –  Stéphane Gimenez Sep 1 '11 at 16:48
1  
@StéphaneGimenez The command utility suppresses alias and function lookup only. It also has an effect on special built-ins (see the spec for details). command cd should always run the build-in. Zsh is non-standard by default, you need to set the posix_builtins option to make it behave according to the standard. –  Gilles Sep 1 '11 at 23:21

c should be exactly equivalent to cd. I expect you'll see the same error from cd dir as from c dir, and that c alone works.

cd won't work the way you've defined it, because aliases perform a simple text substitution. cd dir is expanded to cd; ls -r --time=atime dir. Aliases are pretty much limited to giving a command a shorter name or providing default options, e.g. alias c=cd or alias cp='cp -i'. For anything more complex, such as running several commands, use a function.

cd () {
  command cd "$@" &&
  ls -r --time=atime
}

See also bash functions vs scripts, How to pass parameter to alias?.

share|improve this answer
    
Thank you. You're right c and cd makes no difference. I will accept enzotib answer because it's larger, but your answer gives me the feeling of understanding and the ability to accept his answer. So it belongs to accepted too. –  xralf Sep 2 '11 at 12:04

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.