|
Manipulating Files in Linux
Manipulating
Files
This
page is intended to help the Linux newbie come up to speed on
core file handling commands including file permissions. Brought
to you by Mark Rais, our senior editor. To read comands for
Directories please click here.
Included in this
section are the commands needed to copy, delete, move, and rename
files. Security and permissions are also reviewed below in the
chmod command.
A beginner?
Then it may help you to type the command ls -alt to list all of your
current files and directories before you start, so you can see
your directory and files listed.
Already have experience? Then please skip to Commands for Guru Wanna-bees.
NOTE:
All of these commands should work from your command
prompt (regardless which shell you're using). And of course, if
they don't work or help you, I apologize.
Manipulating Files
Command
|
Summary Use |
| chmod |
The
chmod command allows you to alter access
rights to files and directories. All files and
directories have security permissions that grant the user
particular groups’ or all other users’ access.
To view your files' settings, at the shell prompt type:
ls -alt
You should see some files with the following in front of
them (an example follows):
total
4
drwxrwsr-x 7 reallyli reallyli 1024 Apr 6 14:30 .
drwxr-s--x 22 reallyli reallyli 1024 Mar 30 18:20 ..
d-wx-wx-wx 3 reallyli reallyli 1024 Apr 6 14:30 content
drwxr-xr-x 2 reallyli reallyli 1024 Mar 25 20:43 files
What do the letters mean in front of the files/directories
mean?
r indicates that it is readable (someone
can view the file’s contents)
w indicates that it is writable (someone
can edit the file’s contents)
x indicates that it is executable (someone
can run the file, if executable)
- indicates that no permission to
manipulate has been assigned
When listing your files, the first character lets you
know whether you’re looking at a file or a directory.
It’s not part of the security settings. The next
three characters indicate Your access
restrictions. The next three indicate your group's
permissions, and finally other users'
permissions.Use chmod followed by the permission you are
changing. In very simple form this would be:
chmod 755 filename
The example above will grant you full rights, group
rights to execute and read, and all others access to
execute the file.
| |
# |
Permission |
| |
7 |
full |
| |
6 |
read
and write |
| |
5 |
read
and execute |
| |
4 |
read
only |
| |
3 |
write
and execute |
| |
2 |
write
only |
| |
1 |
execute
only |
| |
0 |
none |
Still confused? Use
the table above to define the settings for the three
"users." In the command, the first number
refers to your permissions, the second
refers to group, and the third refers to
general users.
Typing the command:
chmod 751 filename
gives you full
access, the group read and execute, and all
others execute only permission.
|
| cp |
Type
cp followed by the name of an existing file and the name
of the new file.
Ex:
cp newfile newerfile
To copy a file to a different directory (without changing
th
e file’s name), specify the directory instead of
the new
filename. Ex:
cp newfile testdir
To copy a file to a different directory and create a new
file name, you need to specify a directory/a new file
name. Ex:
cp newfile testdir/newerfile
cp newfile ../newerfile
The .. represents one directory up in the hierarchy.
|
| file |
Type
file followed by the name of an existing file in the directory.
Ex:
file emergency3_demo.exe
OUTPUT: MS-DOS executable (EXE)
This command allows you to figure out what the file type is and how to use it. For instance the command will tell you whether it is an executable, a compressed file and which type, or something unusual.
This command is simplistic, but often can allow you to determine why a file does not respond the way you expect.
|
| mv |
Type
mv followed by the current name of a file and the new
name of the file.
Ex:
mv oldfile newfile Type mv
followed by the name of a file and the new directory
where you'd like to place the file. Ex:
mv newfile testdir
This moves the file named newfile to an existing
directory named testdir. Be certain you’re
specifying a directory
name or the mv command alters the name of the file
instead of moving it.
|
| rm |
Type rm followed by the name of
a file to remove the file.
Ex:
rm newfile
Use the wildcard character to remove several files at
once. Ex:
rm n*
This command removes all files beginning with n.
Type rm -i followed by a filename if you’d like to
be prompted before the file is actually removed. Ex:
rm -i newfile
rm -i n*
By using this option, you have a chance to verify the
removal of each file. The -i option is very handy when
removing
a number of files using the wildcard character *.
|
This list only has items related to files, but this link will take you to
the page related to commands for directories.
|
Website for Beginning Linux Users
HOME
MESSAGES
HELP
