The meaning of ./ before a command

Question

While I was executing a C program in terminal I wrote:

gcc -o demo demo.c
./demo

Actually my doubt is why we write ./ before demo and what does it mean?

It means "in the current directory". We do this so the operating system recognizes it is a file, not a command. — Joren, Sep 24 '13 at 07:29

score 2 · Answer 1 · edited Sep 24 '13 at 07:36

When we execute any command in the terminal it is going to look for it in the PATH environment variable. By using ./ (relative path) we are telling the shell to look for that command in our current directory.

Check echo $PATH

There are two way to execute any commands

Putting its path in the PATH environment variable
Using the full path or a relative path to that programme (Ex. /opt/xyz/bin/someprogramme )

score 1 · Answer 2 · edited May 23 '17 at 12:39

When bash interprets the command line, it looks for commands in locations described in the variable $PATH. To see it type:
echo $PATH
Normally, he current directory is not in that list. The reason for not having the current directory on that list is security.

The ./ says: look in the current directory for my command rather than looking at all the directories specified in $PATH.

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score 0 · Answer 3 · edited Jun 12 '20 at 14:37

0

You put "./" before every program you wish to execute.

Otherwise the terminal doesn't know what to do with "demo" file

edited Jun 12 '20 at 14:37

Community

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answered Sep 24 '13 at 07:03

Naveen

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score 0 · Answer 4 · answered Sep 24 '13 at 08:28

0

The "./" before a file name stand for "execute this file in th current directory" if the file that you want to execute is not in the same directory you are in you will need to specify the path o the file like this:

Xxxxx@xxxx /Documents/filetoexecute

answered Sep 24 '13 at 08:28

Evgeny Danilenko

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The meaning of ./ before a command

4 Answers4

You put "./" before every program you wish to execute.