what is the difference between "./somescript.sh" and ". ./somescript.sh"

Posted by Peter on Stack Overflow See other posts from Stack Overflow or by Peter
Published on 2010-04-14T00:58:13Z Indexed on 2010/04/14 1:03 UTC
Read the original article Hit count: 392

Filed under:

linux

|

shell

This question may sounds silly to you. Today I was following some instructions to install a software in Linux. There was a script that needs to be run first. It set some environment variables.

The instruction told me to execute . ./setup.sh, but I made a mistake by executing ./setup.sh. So the env was not set. Finally I noticed this and proceeded.

I want to know what exactly is the difference between both? I am completely new to Linux so please be as elaborate as possible.

© Stack Overflow or respective owner

Related posts about linux

apt-get install and update fail

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've got a problem with apt-get update and apt-get install ... commands . every time update or installing fails and errors are : Get:1 http://dl.google.com stable Release.gpg [198B] Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en_US Get:2 http://dl… >>> More
kernel module compiling error

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is… >>> More
Build-Essentials installation failing

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I am having trouble accessing the several critical header files that show to be a part of the build process. The "Ubuntu Software Center" shows "Build Essentials" as installed: Next I did the following two commands, which did not improve the problem: ~$ sudo apt-get install build-essential [sudo]… >>> More
Updating Debian kernel

as seen on Super User - Search for 'Super User'
I'm trying to update my Debian machine to 2.6.32-46 (which is the new stable). However, after doing apt-get update my apt-cache search linux-image shows me: linux-headers-2.6.32-5-486 - Header files for Linux 2.6.32-5-486 linux-headers-2.6.32-5-686-bigmem - Header files for Linux 2.6.32-5-686-bigmem linux-headers-2… >>> More
Serial connection over a single USB cable (Windows to linux, or linux to linux)

as seen on Server Fault - Search for 'Server Fault'
I'm helping out with a project for an embedded device that only has USB and no serial. This device is running Linux. These days, when we need to connect to a serial port on a device we typically use a USB to serial adapter (on something like a phone system or a load balancing device, etc). I would… >>> More

Related posts about shell

How to restrict the users' shell allowing to execute shell programs

as seen on Server Fault - Search for 'Server Fault'
Is it possible to prevent any user to not use commands like ls, rm and other system commands which could harm the system. But the users should be able to execute shell programs. >>> More
Shell extension installation not recognized by Windows 7 64-bit shell

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a Copy Hook Handler shell extension that I'm trying to install on Windows 7 64-bit. The shell extension DLL is compiled in two separate versions for 32-bit and 64-bit Windows. The DLL implements DLLRegisterServer which adds the necessary registry entries. After adding the registry entries… >>> More
Running shell commands without a shell window

as seen on Stack Overflow - Search for 'Stack Overflow'
With either subprocess.call or subprocess.Popen, executing a shell command makes a shell window quicky appear and disappear. How can I run the shell command without the shell window? >>> More
Why can't I reinstall MySQL?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've been looking all around the Internet for an answer but didn't find anything. I hope you can help me now. I have a server with MySQL. From one day to another, MySQL didn't let me enter with my root password anymore (accsess denied for user 'root'@'localhost' using password: 'YES'). So I tried… >>> More
Bash/shell script - shell output redirection inside a function

as seen on Stack Overflow - Search for 'Stack Overflow'
function grabSourceFile { cd /tmp/lmpsource wget $1 > $LOG baseName=$(basename $1) tar -xvf $baseName > $LOG cd $baseName } When I call this function The captured output is not going to the log file. The output redirection works fine until I call the… >>> More