What is the difference between these two commands which are used to run shell script?

Question

Here I have one script which exporting some necessary path in Linux. After running this script I have to run some other scripts.

I have two scripts

1 imp         


        

Answer 1

The difference between the two invocations is that ./import.sh is executing import.sh as a program, and . ./import.sh is evaluating it in your shell.

If "import.sh" were an ELF program (a compiled binary, not a shell script), . ./import.sh would not work.

If import.sh had a shebang at the top (like #!/bin/perl), you'd be in for a nasty surprise and a huge number of error messages if you tried to do . ./import.sh - unless the shebang happened to match your current shell, in which case it would accidentally work. Or if the Perl code were to somehow be a valid Bash script, which seems unlikely.

. ./import.sh is equivalent to source import.sh, and doesn't require that the file have the execute bit set (since it's interpreted by your already-running shell instead of spawned via exec). I assume this is the source of your error. Another difference is that ./import.sh runs in the current shell instead of a subshell, so any non-exported environment variables will affect the shell you used for the launch!

So, they're actually rather different. You usually want to ./import.sh unless you know what you're doing and understand the difference.