CODEWITHSUNDEEP
bashshellcommand-line
Venning
Venning

Reputation: 862

Echo directory after change?

(Since I couldn't find an explicit answer to this anywhere and I find it useful, I thought I would add it to SO. Better alternatives welcome.)

In Bash, how do you alias cd to echo the new working directory after a change? Like this:

$ pwd
/some/directory
$ cd newness
/some/directory/newness
$

Something simple like alias cd='cd "$@" && pwd' doesn't work. For some reason, Bash responds as though you used cd - and returns to $OLDPWD and you get caught in a loop. I don't understand this behavior.

Upvotes: 2

Views: 462

Answers (2)

Venning
Venning

Reputation: 862

Apparently, you need to do this through a function:

function mycd() {
  cd "$@" && pwd
}
alias cd=mycd

However, if you use cd - you wind up printing the directory twice, so this is more robust:

function mycd() {
  if [ "$1" == "-" ]; then
    cd "$@"
  else
    cd "$@" && pwd
  fi
}
alias cd=mycd

I may be missing some edge cases, like cd -P - and cd -L -, though I don't know if those even make sense.

(See Adrian Frühwirth's answer below for the reason why a simple alias doesn't work and why I feel dumb now.)

Upvotes: 2

Adrian Frühwirth
Adrian Frühwirth

Reputation: 45576

The alias doesn't work because aliases don't support arguments, so you cannot chain commands that require parameters. Because of this cd "$@" doesn't make sense in the context of an alias and whatever argument you supply to an alias just gets appended:

$ alias foo='echo "[$@]" && echo'
$ foo bar
[]
bar

Obviously, that's not what you want and exactly why you need to resort to a function.

Upvotes: 0

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