terminal commands in ubuntu

tigertim71 · 05-18-2009, 05:57 PM

If I put in the terminal

Code:

cmp abc.txt acd.txt

, this isn't recognised (although this seems to be what is suggested in training manuals).

However, if I put in the full file path, instead of the file name (as above) it is accepted e.g.

Code:

/home/timk/Documents/abc.txt.

What's the best way to do this without writing out the whole file path?

colucix · 05-18-2009, 06:06 PM

You can't. If the file is not in your current directory, you must specify a path. If you use the absolute path you can run that command from any place in the directory tree. If you use a relative path you have to know the position of the file in respect of your current directory. For example:

Code:

$ cd
$ pwd
/home/timk
$ cmp Documents/abc.txt Documents/acd.txt

tigertim71 · 05-19-2009, 01:02 AM

OK, thanks. I suppose the above code would be normal for someone wanting to perform internal commands on a regular basis...

colucix · 05-19-2009, 02:57 AM

You can spare typing the full or relative path of the commands (if they are in a place included in the PATH environment variable) but for files you have always to tell the system where the files are. The unique search path for files is the current directory, whereas for executables (commands) the search path can have multiple directories (as specified by echo $PATH).

tigertim71 · 05-19-2009, 11:41 AM

Was just wondering about the

Code:

in the above code - is this needed and what does it stand for?

I'm just not sure I understood fully the previous answer.

repo · 05-19-2009, 11:43 AM

$ is the promt from a user
# is the prompt from root

Code:

repo@cannabis:~$ su
Password: 
cannabis:/home/repo#

colucix · 05-19-2009, 11:53 AM

As repo said. I put the prompt in the posted code to distinguish between the commands I type and the output I get:

Code:

$ whoami   ### This is the command
colucix    ### This is the output

tigertim71 · 05-19-2009, 05:14 PM

This makes perfect sense now, and I can understand this from the setup process of various Linux apps.

It's interesting that the terminal in Ubuntu is defaulted to $ , however Puppy and Knoppix are in root with #, but I suppose the programmers of each application had something different in mind, with Puppy and Knoppix more suited to being used as live cds.

chrism01 · 05-20-2009, 12:36 AM

No, as pointed out the default prompt char/string is '$' if you are not root, '#' if you are root.
However you can customise it if you want (google "linux PS1").

Quads · 05-20-2009, 12:37 AM

Quote:

Originally Posted by tigertim71

This makes perfect sense now, and I can understand this from the setup process of various Linux apps.

It's interesting that the terminal in Ubuntu is defaulted to $ , however Puppy and Knoppix are in root with #, but I suppose the programmers of each application had something different in mind, with Puppy and Knoppix more suited to being used as live cds.

I don't know about Knoppix, but in Puppy you are always root.