mkdir - make directories
Usage
mkdir [OPTION] DIRECTORY
Options
Create the DIRECTORY(ies), if they do not already exist.
Mandatory arguments to long options are mandatory for
short options too.
-m, mode=MODE set permission mode (as in chmod), not
rwxrwxrwx - umask
-p, parents no error if existing, make parent
directories as needed
-v, verbose print a message for each created
directory
-help display this help and exit
-version output version information and exit
cd - change directories
Use
cd to change directories. Type cd followed by the name of a directory to access
that directory.Keep in mind that you are always in a directory and can navigate
to directories hierarchically above or below.
mv- change the name of a directory
Type mv followed by the current name of a directory and the new
name of the directory.
Ex: mv testdir newnamedir
pwd - print working directory
will show you the full path to the directory you are currently
in. This is very handy to use, especially when performing some of the other
commands on this page
rmdir - Remove an existing directory
rm -r
Removes directories and files within the directories
recursively.
chown - change file owner and group
Usage
chown [OPTION] OWNER[:[GROUP]] FILE
chown [OPTION] :GROUP FILE
chown [OPTION] --reference=RFILE FILE
Options
Change the owner and/or group of each FILE to OWNER and/or
GROUP. With --reference, change the owner and group of each FILE to those
of RFILE.
-c, changes like verbose but report only when a change is
made
-dereference affect the referent of each symbolic link,
rather than the symbolic link itself
-h, no-dereference affect each symbolic link instead of
any referenced file (useful only on systems that can
change the ownership of a symlink)
-from=CURRENT_OWNER:CURRENT_GROUP
change the owner and/or group of each file only if
its current owner and/or group match those specified here. Either
may be omitted, in which case a match is not required for the
omitted attribute.
-no-preserve-root do not treat `/' specially (the default)
-preserve-root fail to operate recursively on `/'
-f, -silent, -quiet suppress most error messages
-reference=RFILE use RFILE's owner and group rather than the
specifying OWNER:GROUP values
-R, -recursive operate on files and directories recursively
-v, -verbose output a diagnostic for every file processed
The following options modify how a hierarchy is traversed
when the -R option is also specified. If more than one is specified, only
the final one takes effect.
-H if a command line argument is a
symbolic link to a directory, traverse it
-L traverse every symbolic link to a
directory encountered
-P do not traverse any symbolic links
(default)
chmod - change file access permissions
Usage
chmod [-r] permissions filenames
r Change the permission on files that are in the
subdirectories of the directory that you are currently in.
permission Specifies the rights that
are being granted. Below is the different rights that you can grant in an
alpha numeric format.filenames File or directory that you are
associating the rights with Permissions
u - User who owns the file.
g - Group that owns the file.
o - Other.
a - All.
r - Read the file.
w - Write or edit the file.
x - Execute or run the file as a program.
Numeric Permissions:
CHMOD can also to attributed by using Numeric Permissions:
400 read by owner
040 read by group
004 read by anybody (other)
200 write by owner
020 write by group
002 write by anybody
100 execute by owner
010 execute by group
001 execute by anybody
ls - Short listing of directory contents
-a list hidden files
-d list the name of
the current directory
-F show directories
with a trailing '/'
executable files with a trailing '*'
-g show group
ownership of file in long listing
-i print the inode
number of each file
-l long listing giving
details about files and directories
-R list all
subdirectories encountered
-t sort by time
modified instead of name
cp - Copy files
cp myfile yourfile
Copy the files "myfile" to the file
"yourfile" in the current working directory. This command will create
the file "yourfile" if it doesn't exist. It will normally overwrite
it without warning if it exists.
cp -i myfile yourfile
With the "-i" option, if the file "yourfile"
exists, you will be prompted before it is overwritten.
cp -i /data/myfile
Copy the file "/data/myfile" to the current working
directory and name it "myfile". Prompt before overwriting the
file.
cp -dpr srcdir destdir
Copy all files from the directory "srcdir" to the
directory "destdir" preserving links (-poption), file attributes (-p
option), and copy recursively (-r option). With these options, a directory and
all it contents can be copied to another dir
ln - Creates a symbolic link to a file.
ln -s test symlink
Creates a symbolic link named symlink that points to the file
test Typing "ls -i test symlink" will show the two files are
different with different inodes. Typing "ls -l test symlink" will
show that symlink points to the file test.
locate - A fast database driven file locator.
slocate -u
This command builds the slocate database. It will take several
minutes to complete this command.This command must be used before
searching for files, however cron runs this command periodically on most
systems.locate whereis Lists all files whose names contain the string
"whereis". directory.
more - Allows file contents or piped output to be sent to the
screen one page at a time
less - Opposite of the more command
cat - Sends file contents to standard output. This is a way to list
the contents of short files to the screen. It works well with piping.
whereis - Report all known
instances of a command
wc - Print byte, word, and line counts
bg
bg jobs Places the current job (or, by using the alternative form, the
specified jobs) in the background, suspending its execution so that a new user
prompt appears immediately. Use the jobs command to discover the identities of
background jobs.
cal month year - Prints a
calendar for the specified month of the specified year.
cat files - Prints
the contents of the specified files.
clear - Clears the terminal screen.
cmp file1 file2 - Compares two files,
reporting all discrepancies. Similar to the diff command, though the output
format differs.
diff file1 file2 - Compares
two files, reporting all discrepancies. Similar to the cmp command, though the
output format differs.
dmesg - Prints the messages resulting from the most
recent system boot.
fg
fg jobs - Brings the current job (or the specified jobs) to the foreground.
file files - Determines and prints a
description of the type of each specified file.
find path -name pattern -print
Searches the specified path for files with names matching the
specified pattern (usually enclosed in single quotes) and prints their names.
The find command has many other arguments and functions; see the online
documentation.
finger users - Prints descriptions of the
specified users.
free - Displays the amount of used
and free system memory.
ftp hostname
Opens an FTP connection to the specified host, allowing files to
be transferred. The FTP program provides subcommands for accomplishing file
transfers; see the online documentation.
head files - Prints the first several
lines of each specified file.
ispell files - Checks the spelling of the
contents of the specified files.
kill process_ids
kill - signal process_ids
kill -l
Kills the specified processes, sends the specified processes the
specified signal (given as a number or name), or prints a list of available
signals.
killall program
killall - signal program
Kills all processes that are instances of the specified program or
sends the specified signal to all processes that are instances of the specified
program.
mail - Launches a simple mail client that permits
sending and receiving email messages.
man title
man section title - Prints the specified man
page.
ping host - Sends an
echo request via TCP/IP to the specified host. A response confirms that the
host is operational.
reboot - Reboots the system (requires root privileges).
shutdown minutes
shutdown -r minutes
Shuts down the system after the specified number of minutes
elapses (requires root privileges). The -r option causes the system to be
rebooted once it has shut down.
sleep time - Causes the command interpreter to pause for the specified number
of seconds.
sort files - Sorts the specified files.
The command has many useful arguments; see the online documentation.
split file - Splits a file into several
smaller files. The command has many arguments; see the online documentation
sync - Completes all pending input/output operations
(requires root privileges).
telnet host - Opens a
login session on the specified host.
top - Prints a display of system processes that's continually updated
until the user presses the q key.
traceroute host - Uses
echo requests to determine and print a network path to the host.
uptime - Prints the system uptime.
w - Prints the current system users.
wall - Prints a message to each user except those who've disabled
message reception. Type Ctrl-D to end the message.
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