UNIX for Dummies Questions & Answers

Please explain this strange behavior to me

Code:

bash-2.03$ ls -l abc
-rw-------   1   bashboy  users        319 Sep 21 18:02 abc
bash-2.03$ ./abc
bash: ./abc: Permission denied
bash-2.03$ . abc
Successfully run

I wanted to ask how the file executes without the execute permissions when we source the file.

Thank you

Simple answer is it's not executing. It's being interpreted by the current shell.

Executing means "exec()" was called, which, in this case, is not the case.

Isnt this the same case, when a script without execute bit set and passed to the base shell as an argument ?

Code:

zsh script.zsh

Here the file script.zsh is just an argument to the base binary zsh

Unix programming Learning the Korn Shell, p 25, O'Reilly

There are three ways to run a script in Korn Shell (ksh):

1) $ . scriptname
Here you are running the script without creating a subshell, meaning that the new settings will be still in this shell after running the script. It's like copy/paste each line of the script in the shell.
This is also called sourcing because in csh and tcsh this is executed by running: $ sourse scriptname.
Also to run a script this way the script do not need execution permissions.

2) $ ./scritpname
Run the script in a subshell, after the script executes the shell will not have the new settings. Script need execution permissions.

3) $ scriptname
Run the script in a subshell, if . (current dir) is part of your cmd, searches in $PATH. The script needs execution permissions.