CODEWITHSUNDEEP
linuxbashshell
ashokgelal
ashokgelal

Reputation: 81558

Why can't I change directories using "cd" in a script?

I'm trying to write a small script to change the current directory to my project directory:

#!/bin/bash
cd /home/tree/projects/java

I saved this file as proj, added execute permission with chmod, and copied it to /usr/bin. When I call it by: proj, it does nothing. What am I doing wrong?

Upvotes: 838

Views: 769046

Answers (30)

Matt Thomas
Matt Thomas

Reputation: 1465

To make a bash script that will cd to a select directory:

Create the script file

#!/bin/sh
# file : /scripts/cdjava
#
cd /home/askgelal/projects/java

Then create an alias in your startup file.

#!/bin/sh
# file /scripts/mastercode.sh
#
alias cdjava='. /scripts/cdjava'

I created a startup file where I dump all my aliases and custom functions. Then I source this file into my .bashrc to have it set on each boot.

For example, create a master aliases/functions file: /scripts/mastercode.sh

(Put the alias in this file.)

Then at the end of your .bashrc file:

source /scripts/mastercode.sh

Now itws easy to cd to your java directory, just type cdjava and you are there.

Upvotes: 103

intika
intika

Reputation: 9792

As explained on the other answers, you have changed the directory, but only within the sub-shell that runs the script. this does not impact the parent shell.

One solution is to use bash functions instead of a bash script; by placing your bash code into a function. That makes the function available as a command and then, this will be executed without a child process and thus any cd command will impact the caller shell.

Bash functions:

One feature of the bash profile is to store custom functions that can be run in the terminal or in bash scripts the same way you run application/commands this also could be used as a shortcut for long commands.

To make your function efficient system widely you will need to copy your function at the end of several files

/home/user/.bashrc
/home/user/.bash_profile
/root/.bashrc
/root/.bash_profile

You can sudo kwrite /home/user/.bashrc /home/user/.bash_profile /root/.bashrc /root/.bash_profile to edit/create those files quickly

Howto:

Copy your bash script code inside a new function at the end of your bash's profile file and restart your terminal, you can then run cdd or whatever the function you wrote.

Script Example

Making shortcut to cd .. with cdd

cdd() {
  cd ..
}

ls shortcut

ll() {
  ls -l -h
}

ls shortcut

lll() {
  ls -l -h -a
}

Upvotes: 0

zyfyy
zyfyy

Reputation: 363

instead of excute a script file and cd to the certain folder,

we can make it by:

  • source or . certain shell script
  • alias the cd command
  • define a function ant cd to folder

examples:

. script
# or
source script

alias ghqc='cd $(ghq root)/$(ghq list | fzf)'

ghqc() {
  cd $(ghq root)/$1
}

Upvotes: 0

Serge Stroobandt
Serge Stroobandt

Reputation: 31598

Use exec bash at the end

A bash script operates on its current environment or on that of its children, but never on its parent environment.

However, this question often gets asked because one wants to be left at a (new) bash prompt in a certain directory after execution of a bash script from within another directory.

If this is the case, simply execute a child bash instance at the end of the script:

#!/usr/bin/env bash
cd /home/tree/projects/java
echo -e '\nHit [Ctrl]+[D] to exit this child shell.'
exec bash

To return to the previous, parental bash instance, use Ctrl+D.

Update

At least with newer versions of bash, the exec on the last line is no longer required. Furthermore, the script could be made to work with whatever preferred shell by using the $SHELL environment variable. This then gives:

#!/usr/bin/env bash
cd desired/directory
echo -e '\nHit [Ctrl]+[D] to exit this child shell.'
$SHELL

Upvotes: 42

Asclepius
Asclepius

Reputation: 63514

This combines the answer by Serge with an unrelated answer by David. It changes the directory, and then instead of forcing a bash shell, it launches the user's default shell. It however requires both getent and /etc/passwd to detect the default shell.

#!/usr/bin/env bash
cd desired/directory
USER_SHELL=$(getent passwd <USER> | cut -d : -f 7)
$USER_SHELL

Of course this still has the same deficiency of creating a nested shell.

Upvotes: 0

chris
chris

Reputation: 29

I did the following:

create a file called case

paste the following in the file:

#!/bin/sh

cd /home/"$1"

save it and then:

chmod +x case

I also created an alias in my .bashrc:

alias disk='cd /home/; . case'

now when I type:

case 12345

essentially I am typing:

cd /home/12345

You can type any folder after 'case':

case 12

case 15

case 17

which is like typing:

cd /home/12

cd /home/15

cd /home/17

respectively

In my case the path is much longer - these guys summed it up with the ~ info earlier.

Upvotes: 2

ZakS
ZakS

Reputation: 1131

I have to work in tcsh, and I know this is not an elegant solution, but for example, if I had to change folders to a path where one word is different, the whole thing can be done in the alias

a alias_name 'set a = `pwd`; set b = `echo $a | replace "Trees" "Tests"` ; cd $b'

If the path is always fixed, the just

a alias_name2 'cd path/you/always/need'

should work In the line above, the new folder path is set

Upvotes: 0

Yuri Nudelman
Yuri Nudelman

Reputation: 2943

It is an old question, but I am really surprised I don't see this trick here

Instead of using cd you can use

export PWD=the/path/you/want

No need to create subshells or use aliases.

Note that it is your responsibility to make sure the/path/you/want exists.

Upvotes: 0

18446744073709551615
18446744073709551615

Reputation: 16852

Note the discussion How do I set the working directory of the parent process?

It contains some hackish answers, e.g. https://stackoverflow.com/a/2375174/755804 (changing the parent process directory via gdb, don't do this) and https://stackoverflow.com/a/51985735/755804 (the command tailcd that injects cd dirname to the input stream of the parent process; well, ideally it should be a part of bash rather than a hack)

Upvotes: 0

Sagar
Sagar

Reputation: 1335

You can use . to execute a script in the current shell environment:

. script_name

or alternatively, its more readable but shell specific alias source:

source script_name

This avoids the subshell, and allows any variables or builtins (including cd) to affect the current shell instead.

Upvotes: 59

jithu83
jithu83

Reputation: 579

This should do what you want. Change to the directory of interest (from within the script), and then spawn a new bash shell.

#!/bin/bash

# saved as mov_dir.sh
cd ~/mt/v3/rt_linux-rt-tools/
bash

If you run this, it will take you to the directory of interest and when you exit it it will bring you back to the original place.

root@intel-corei7-64:~# ./mov_dir.sh

root@intel-corei7-64:~/mt/v3/rt_linux-rt-tools# exit
root@intel-corei7-64:~#

This will even take you to back to your original directory when you exit (CTRL+d)

Upvotes: 2

Krish
Krish

Reputation: 477

You can create a function like below in your .bash_profile and it will work smoothly.

The following function takes an optional parameter which is a project. For example, you can just run

cdproj

or

cdproj project_name

Here is the function definition.

cdproj(){
    dir=/Users/yourname/projects
    if [ "$1" ]; then
      cd "${dir}/${1}"
    else
      cd "${dir}"
    fi
}

Dont forget to source your .bash_profile

Upvotes: 3

warhansen
warhansen

Reputation: 736

simply run:

cd /home/xxx/yyy && command_you_want

Upvotes: 21

Tzachi.e
Tzachi.e

Reputation: 1831

The cd is done within the script's shell. When the script ends, that shell exits, and then you are left in the directory you were. "Source" the script, don't run it. Instead of:

./myscript.sh

do

. ./myscript.sh

(Notice the dot and space before the script name.)

Upvotes: 183

Gauthier
Gauthier

Reputation: 42015

You need no script, only set the correct option and create an environment variable.

shopt -s cdable_vars

in your ~/.bashrc allows to cd to the content of environment variables.

Create such an environment variable:

export myjava="/home/tree/projects/java"

and you can use:

cd myjava

Other alternatives.

Upvotes: 0

workdreamer
workdreamer

Reputation: 2856

On my particular case i needed too many times to change for the same directory. So on my .bashrc (I use ubuntu) i've added the

1 -

$ nano ~./bashrc

 function switchp
 {
    cd /home/tree/projects/$1
 }

2-

$ source ~/.bashrc

3 -

$ switchp java

Directly it will do: cd /home/tree/projects/java

Hope that helps!

Upvotes: 12

thomasd
thomasd

Reputation: 1022

While sourcing the script you want to run is one solution, you should be aware that this script then can directly modify the environment of your current shell. Also it is not possible to pass arguments anymore.

Another way to do, is to implement your script as a function in bash.

function cdbm() {
  cd whereever_you_want_to_go
  echo "Arguments to the functions were $1, $2, ..."
}

This technique is used by autojump: http://github.com/joelthelion/autojump/wiki to provide you with learning shell directory bookmarks.

Upvotes: 3

Greg Hewgill
Greg Hewgill

Reputation: 994371

Shell scripts are run inside a subshell, and each subshell has its own concept of what the current directory is. The cd succeeds, but as soon as the subshell exits, you're back in the interactive shell and nothing ever changed there.

One way to get around this is to use an alias instead:

alias proj="cd /home/tree/projects/java"

Upvotes: 703

J. A. Faucett
J. A. Faucett

Reputation: 410

You can combine an alias and a script,

alias proj="cd \`/usr/bin/proj !*\`"

provided that the script echos the destination path. Note that those are backticks surrounding the script name. 

For example, your script could be

#!/bin/bash
echo /home/askgelal/projects/java/$1

The advantage with this technique is that the script could take any number of command line parameters and emit different destinations calculated by possibly complex logic.

Upvotes: 7

godzilla
godzilla

Reputation: 1010

I have a simple bash script called p to manage directory changing on
github.com/godzilla/bash-stuff
just put the script in your local bin directory (/usr/local/bin)
and put

alias p='. p'

in your .bashrc

Upvotes: -1

mihai.ciorobea
mihai.ciorobea

Reputation: 741

In your ~/.bash_profile file. add the next function

move_me() {
    cd ~/path/to/dest
}

Restart terminal and you can type

move_me

and you will be moved to the destination folder.

Upvotes: 5

Max
Max

Reputation: 3

You can execute some lines in the same subshell if you end lines with backslash.

cd somedir; \
pwd

Upvotes: -3

Jack Bauer
Jack Bauer

Reputation: 47

You can use the operator && :

cd myDirectory && ls

Upvotes: 3

Lane Roathe
Lane Roathe

Reputation: 500

If you are using fish as your shell, the best solution is to create a function. As an example, given the original question, you could copy the 4 lines below and paste them into your fish command line:

function proj
   cd /home/tree/projects/java
end
funcsave proj

This will create the function and save it for use later. If your project changes, just repeat the process using the new path.

If you prefer, you can manually add the function file by doing the following:

nano ~/.config/fish/functions/proj.fish

and enter the text:

function proj
   cd /home/tree/projects/java
end

and finally press ctrl+x to exit and y followed by return to save your changes.

(NOTE: the first method of using funcsave creates the proj.fish file for you).

Upvotes: 0

Adam Liss
Adam Liss

Reputation: 48330

You're doing nothing wrong! You've changed the directory, but only within the subshell that runs the script.

You can run the script in your current process with the "dot" command:

. proj

But I'd prefer Greg's suggestion to use an alias in this simple case.

Upvotes: 564

DigitalRoss
DigitalRoss

Reputation: 146211

The cd in your script technically worked as it changed the directory of the shell that ran the script, but that was a separate process forked from your interactive shell.

A Posix-compatible way to solve this problem is to define a shell procedure rather than a shell-invoked command script.

jhome () {
  cd /home/tree/projects/java
}

You can just type this in or put it in one of the various shell startup files.

Upvotes: 236

kaelhop
kaelhop

Reputation: 399

I got my code to work by using. <your file name>

./<your file name> dose not work because it doesn't change your directory in the terminal it just changes the directory specific to that script.

Here is my program

#!/bin/bash 
echo "Taking you to eclipse's workspace."
cd /Developer/Java/workspace

Here is my terminal 

nova:~ Kael$ 
nova:~ Kael$ . workspace.sh
Taking you to eclipe's workspace.
nova:workspace Kael$

Upvotes: 27

rjmoggach
rjmoggach

Reputation: 1470

You can combine Adam & Greg's alias and dot approaches to make something that can be more dynamic—

alias project=". project"

Now running the project alias will execute the project script in the current shell as opposed to the subshell.

Upvotes: 8

Gene T
Gene T

Reputation: 5176

to navigate directories quicky, there's $CDPATH, cdargs, and ways to generate aliases automatically

http://jackndempsey.blogspot.com/2008/07/cdargs.html

http://muness.blogspot.com/2008/06/lazy-bash-cd-aliaes.html

https://web.archive.org/web/1/http://articles.techrepublic%2ecom%2ecom/5100-10878_11-5827311.html

Upvotes: 6

Thevs
Thevs

Reputation: 3251

You can do following:

#!/bin/bash
cd /your/project/directory
# start another shell and replacing the current
exec /bin/bash

EDIT: This could be 'dotted' as well, to prevent creation of subsequent shells.

Example:

. ./previous_script  (with or without the first line)

Upvotes: 13

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