A free Basic UNIX-training with muLinux

Copy, Move, Rename, Link

Copying files and directories

Copying a file

/# cd /etc
/etc# cp passwd passwd.original

In this example you have cloned the file passwd. In case you made a mistake in editing passwd, you just need to delete passwd and replace it with passwd.original by copying the original file.

The copied file will have the same permissions and retains the last change date. The user who wants to copy a file must have permission to read the file and needs write permission in the directory where the file will be created. The user will immediately be "owner" of the new file. If the "old" file wasn't his file he requires permission there too.

/etc# ls -l passwd*
1 -rw-r--r--   1 craxi    psi           708 Feb 27  1999 passwd
1 -rw-r--r--   1 root     root          708 Oct 31 13:18 passwd.original

You can also copy a file to the floppy. For this the floppy needs to be mounted on /a.

/etc# cp passwd /a

Copying more files

/etc# cp passwd passwd.original /a

The original file /a/passwd is overwritten. You can test this with following command. Let's have a look at the change date.

/etc# ls -l /a

If you want to be asked for confirmation, you need to add the option -i (interactive).

/etc# cp -i passwd passwd.original /a
cp: overwrite `/a/passwd`? y
cp: overwrite `/a/passwd.original`? y
/etc# _

Using the wildcard symbol * several files can be copied.

/etc# cp i* /a

Now, all file names starting with an i, are copied to the floppy.

Copy directories with contents

/etc# cp -r /etc/ppp /a

The option -r you also used with the command rm. Now you will use it to remove the contents of the floppy.

/etc# rm -r /a/*

Move and rename files

/etc# mv passwd /a

This puts the file passwd on the floppy, and removes it from the directory /etc which would have fatal consequences in a "real" Unix system. That's why you must move the file back.

Renaming files

/etc# cd /bin
/bin# mv ls dir
/bin# ls
/bin/ls: not found
/bin# dir
directory-contents

Links - More names for one file

/bin# ln ls dir

Now the command ls works just like dir.

Another use of this command would be to use the floppy as our home directory /home/Robert. Like this you can work in your directory while at the same time everything is saved on the floppy disk. Please use your own name for your home directory.

/bin# ln /a /home/Robert
Please use "ln -s" to link directories.
/bin# _

What now? It seems that by linking directories you need to add the option -s (softlink):

/bin# ln -s /a /home/Robert
/bin# ls /home/Robert
contents of the floppy
/bin# _

When you enter into the directory /home/Robert you are in the directory /a.

/bin# cd /a /home/Robert
/a# _