Basic
Linux Commands and file system commands :-
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.
file system commands:
cd Change Directory
chmod Change access permissions
chown Change file owner
chgrp Change group ownership
df Display free disk space
dir Briefly list directory contents
du Estimate file space usage
fdformat Low-level format a floppy disk
fdisk Partition table manipulator for Linux
find Search for files that meet a desired criteria
format Format disks or tapes
fsck File system consistency check and repair.
ln Make links between files
Find files
ls List information about file(s)
mkdir Create new folder(s)
mknod Make block or character special files
mount Mount a file system
umount Unmount a device
mtools Manipulate MS-DOS files
mv Move or rename files or directories
quota Display disk usage and limits
quotacheck Scan a file system for disk usage
quotactl Set disk quotas
cp Copy one or more files to another location
rcp Copy files between two machines.
rm Remove files
rmdir Remove folder(s)
symlink Make a new name for a file
umask Users file creation mask
uniq Uniquify files
v Verbosely list directory contents (`ls -l -b’)
vdir Verbosely list directory contents (`ls -l -b’)
dirs Display list of remembered directories
pushd Save and then change the current directory
popd Restore the previous value of the current directory
dircolors Colour setup for `ls’
dirname Convert a full pathname to just a path
ram ram disk device
sync Synchronize data on disk with memory
chmod Change access permissions
chown Change file owner
chgrp Change group ownership
df Display free disk space
dir Briefly list directory contents
du Estimate file space usage
fdformat Low-level format a floppy disk
fdisk Partition table manipulator for Linux
find Search for files that meet a desired criteria
format Format disks or tapes
fsck File system consistency check and repair.
ln Make links between files
Find files
ls List information about file(s)
mkdir Create new folder(s)
mknod Make block or character special files
mount Mount a file system
umount Unmount a device
mtools Manipulate MS-DOS files
mv Move or rename files or directories
quota Display disk usage and limits
quotacheck Scan a file system for disk usage
quotactl Set disk quotas
cp Copy one or more files to another location
rcp Copy files between two machines.
rm Remove files
rmdir Remove folder(s)
symlink Make a new name for a file
umask Users file creation mask
uniq Uniquify files
v Verbosely list directory contents (`ls -l -b’)
vdir Verbosely list directory contents (`ls -l -b’)
dirs Display list of remembered directories
pushd Save and then change the current directory
popd Restore the previous value of the current directory
dircolors Colour setup for `ls’
dirname Convert a full pathname to just a path
ram ram disk device
sync Synchronize data on disk with memory
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