0

This bash file running on Mac terminal failed to change the directory. Rather reporting it does not exist when it actually does. Any thing I did wrong?

#!/usr/bin/env bash
set -e
read name
APPLICATION_PATH="~/Documents/meteor/apps/$name"
cd "${APPLICATION_PATH}"
  • Try replacing ~ with $HOME. – DopeGhoti Dec 29 '16 at 22:34
5

There are two points:

  • Problems with tilde expansion
  • Problems with sourcing vs. executing.

For the tilde part, a very recent question at superuser was about the same issue (https://superuser.com/questions/1161493/why-bash-script-wont-extend-bashrc/1161496#1161496)

The tilde is expanded before the variable, so the cd cannot find the path. To overcome this, lead the command with eval as such:

eval cd "${APPLICATION_PATH}"

Unfortunately, when you execute the script (I mean, if it is chmod'ed to "+x", calling the path), you will see that the $PWD does not change in the "current shell". However if you add such a line at the end of the script

ls

You will see that, ls is executed at the new working directory. How come?

The answer is here (https://superuser.com/questions/176783/what-is-the-difference-between-executing-a-bash-script-and-sourcing-a-bash-scrip#176788)

Short answer: sourcing will run the commands in the current shell process. executing will run the commands in a new shell process. still confused? then please continue reading the long answer.

Shortly, to change the $PWD at current shell, you should "source" the script as such:

source /path/to/script

or

. /path/to/script

A third point: If you don't want to mess with source or ., you can define an alias in your ~/.bashrc (https://stackoverflow.com/questions/752525/run-bash-script-as-source-without-source-command):

alias mycmd="source mycmd.sh"

  • 1
    I tend to always use $HOME rather than ~ in scripts. Looks better too, in my opinion. – Kusalananda Dec 29 '16 at 22:49
1

you can use tilda '~' you just need to have turned on the proper bash expansion key

set -x

or use either full path '/Volumes/Swap/Apps/...'

use bashrc to set env shortcuts like

export LocalApps=/Users/me/Applications
export SysApps=/Applications

i wouldn't use eval

if you just want to suck in a string from the command line you don't need to use read just grab the arg

if [[ $# -eq 1 ]]; then
    #check if it's directory
    if [[ -d $name ]] ; then
      #do stuff here
    else
      echo 'bomb'
    fi
else
  usage
fi

instead of 'cd-ing' to a directory learn how to use ~+, ~-, pushd and popd, many times you don't need to actually 'cd' into a directory

you might do something this

pushd $SysApps/$name
  do stuff 
popd
0

Don't put ~ inside ""

#!/usr/bin/env bash
set -e
read name
APPLICATION_PATH=~/Documents/meteor/apps/$name
cd "${APPLICATION_PATH}"
pwd

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