Basic Commands

ls - list contents of directories

$ ls
file1  file2  file3

ls -l
In addition to the name of each file, print the file type, permissions, number of hard links, owner name, group name, size in bytes, and timestamp (the modification time unless other times are selected).For files with a time that is more than 6 months old or more than 1 hour into the future, the times.

$ ls -l
total 3
-rw-r--r--   1 guest    users           8 Aug  4 15:56 file1
-rw-r--r--   1 guest    users           8 Aug  5 15:57 file2
-rw-r--r--   1 guest    users           8 Aug  4 15:57 file3

ls -lt
Sort directory contents by timestamp instead of alphabetically, with the newest files listed first.

 $ ls -lt
total 3
-rw-r--r--   1 guest    users           8 Aug  5 15:57 file2
-rw-r--r--   1 guest    users           8 Aug  4 15:57 file3
-rw-r--r--   1 guest    users           8 Aug  4 15:56 file1

cp - copy files

cp [options] source dest

$ ls
file1  file2  file3
$ cp file1 file4
$ ls
file1  file2  file3  file4

mv - rename files

mv [options] source dest mv [options] source... directory

$ ls
file1  file2  file3  file4
$ mv file4 /tmp
$ ls
file1  file2  file3
$ cd /tmp
[guest@linux /tmp]$ ls
file4

$ ls
file1  file2  file3  file4
$ mv file4 file5
$ ls
file1  file2  file3  file5

rm - remove files

$ ls
file1  file2
$ rm file2
$ ls
file1

mkdir - make directories

$ ls
file1
$ mkdir directory
$ ls -lt
total 2
drwxr-xr-x   2 guest    users        1024 Aug  5 11:40 directory/
-rw-r--r--   1 guest    users           8 Aug  4 16:04 file1

rmdir - remove empty directories

$ ls
directory/  file1
$ rmdir directory
$ ls
file1

cat - concatenate files and print on the standard output

$ cat file1
101     3people         2-DK
102     none            1-room
201     2people         2-DK
202     4people         3-LDK

grep - print lines matching a pattern

grep [-cvn] pattern [file1 file2 ...]

Options
-c	Suppress normal output; instead print a count of matching lines for each input file. With the -v,-revert-match option (see below), count non-match
-v	Invert the sense of matching, to select non-matching lines.
-n	Prefix each line of output with the line number within its input file.

$ cat file1
101     3people         2-DK
102     none            1-room
201     2people         2-DK
202     4people         3-LDK

$ cat file2
301     4people         4-DK
302     3people         3-LDK
401     none            2-DK
402     2people         2-DK

$ grep LDK *
file1:202       4people         3-LDK
file2:302       3people         3-LDK

chmod - change the access permissions of files

[root@ns public_html]# ls -l
-rw-------   1 hoge  staff         163 Aug  7 22:39 index.html
[root@ns public_html]# chmod g+r index.html
[root@ns public_html]# ls -l
-rw-r-----   1 hoge  staff         163 Aug  7 22:39 index.html
[root@ns public_html]# chmod 644 index.html
[root@ns public_html]# ls -l
-rw-r--r--   1 hoge  staff         163 Aug  7 22:39 index.html

kill - terminate a process

EX1)

# ps ax | grep dhcpd
  278  ?  S    0:00 /usr/sbin/dhcpd
 7308  p1 S    0:00 grep dhcpd
# kill 278
# ps ax | grep dhcpd
 7310  p1 S    0:00 grep dhcpd

EX2)

# kill `ps ax | awk '/pppd/ {print $1}'`

passwd - update a user's authentication tokens

$ passwd
Changing password for guest
(current) UNIX password:
New UNIX password:
Retype new UNIX password:
passwd: all authentication tokens updated successfully

man - format and display the on-line manual pages

man keyword

$ man ls

LS(1)                                                       LS(1)

NAME
       ls, dir, vdir - list contents of directories

SYNOPSIS
       ls  [-abcdfgiklmnpqrstuxABCFGLNQRSUX1] [-w cols] [-T cols]
       [-I pattern] [--all]  [--escape]  [--directory]  [--inode]
       [--kilobytes]  [--numeric-uid-gid]  [--no-group]  [--hide-
       control-chars] [--reverse] [--size] [--width=cols] [--tab-
       size=cols]  [--almost-all] [--ignore-backups] [--classify]
       [--file-type] [--full-time] [--ignore=pattern] [--derefer-
       ence]     [--literal]     [--quote-name]     [--recursive]
       [--sort={none,time,size,extension}]   [--format={long,ver-
       bose,commas,across,vertical,single-column}]
       [--time={atime,access,use,ctime,status}] [--help]  [--ver-
       sion]  [--color[={yes,no,tty}]]  [--colour[={yes,no,tty}]]
       [name...]

DESCRIPTION
       This documentation is no longer being maintained  and  may
......................................

Back