| wildcard characters |
| * |
- The * wildcard character substitutes for one or more characters in a filename. For instance, to list all the files in your directory that end with .c, enter the command
- ls *.c
|
| ? |
- ? (question mark) serves as wildcard character for any one character in a filename. For instance, if you have files named prog1, prog2, prog3, and prog3 in your directory, the Unix command:
ls prog?
|
| dir |
| Change |
cd dir Change to directory d |
| Make |
mkdir dir Create new directory d |
| Move |
mv dir1 dir2 Rename directory d1 as d2 |
| Remove |
rmdir dir Remove directory d |
| file |
|
| list , no details only names |
ls filename , filename with wildcard character/s. |
| list , details |
ls -1 filename , filename with wildcard character/s. |
| move to directory |
mv filename dirname (wildcard character/s supported) |
| copy file to other/current directory |
cp file directory/newfile or cp directory/oldfile . |
| Delete the file |
rm file , rm -rf directory - Recursively remove files & directly without any warning. |
| file |
file filename , file command tries to determine the file type , text , executable etc after comparing the values in /etc/magic . |
| File edit/create/view |
|
| vi - vi full screen editor |
vi filename , Opens a existing file or creates |
| ed - Line Text editor |
ed filename |
| count - Line, word, & char |
wc filename |
| Text content display - List contents of file at once |
cat filename |
| Text content display by screen : List contents of file screen by screen |
more filename |
| Concatenate - file1 & file2 into file3 |
cat file1 file2 >file3 |
| File operation |
| Change read/write/execute mode of fil |
chmod mode file |
| chown |
chown [-R] [-h] owner[:group] file |
| move (rename ) file |
mv file1 file2 Rename file file1 as file2 |
| Remove |
rm file Delete (remove) file f |
| Compare two files |
cmp file1 file2 |
| Copy file file1 into file2 |
cp file1 file2 |
| Sort Alphabetically |
sort file |
| Sort Numerically |
sort -n file |
| Split f into n-line pieces |
split [-n] f |
| match pattern |
grep pattern file Outputs lines that |
| Lists file differences |
diff file1 file2 |
| head f Output beginning of file |
head file |
| Output end of file |
tail file |
| PROCESS |
| Suspend current process |
CTRL/z * |
| Interrupt processes |
CTRL/c * |
| Stop screen scrolling |
CTRL/s * |
| Resume screen scrolling |
CTRL/q * |
| Sleep for n seconds |
sleep n |
| Print list of jobs |
jobs |
| Kill job n |
kill % |
| Remove process n |
kill -9 n |
| status process status stats |
ps |
| Resume background job n |
bg [%n] |
| Resume foreground job n |
fg [%n] |
| Exit from shell |
exit |
| User admin |
|
| add a new user login to the system |
# useradd -u 655 -g 20 -d /home/ttes testlogin loginname
- -u is userid , if not specified system takes highest available .
- -g group id should be existing in /etc/group , if not specified other or user is assigned.
- -d home directory , default is to use user as the directory name under the home directory.
- loginname - new login name to be created .
#useradd testlogin will create a user by the name ‘testlogin’ with all default values . |
| password Change |
passwd <user> |
| alias (csh/tcsh) - Create command |
alias name1 name2 |
| alias (ksh/bash) - Create alias command |
alias name1=”name2″ |
| alias - Remove alias |
unalias name1[na2...] |
| printer |
|
| Output file f to line printer |
lp -d printer file |
|
|
| System Status |
|
| Display disk quota |
quota |
| Print date & time |
date |
| List logged in users |
who |
| Display current user |
whoami |
| Output user information |
finger [username] |
| Display recent commands |
history |
| Environment Variable |
|
| set |
set command alone displays the environment variables, it is used to set options in ksh like set -o vi |
| export |
export variable , export makes variable visible in sub shells. |
| Set environment variable (csh/tcsh) to value v |
sentenv name v |
| Set environment variable (ksh/bash) to value v |
export name=v example : export TERM=vt100 |
| Connectivity |
|
| Connecting to a remote host |
$telnet hostname/ip address or $telnet Telnet brings up the login prompt of remote host and expects you to enter your user name & password .Without argument it enters command mode (telnet>) and accepts command listed by ? at telnet> prompt.
Communication is not encrypted between two hosts. |
| Securely connecting to a remote host |
- ssh username@hostname or ssh -l username hostname
- Depending on ssh setting for your account you may or may not be asked a password to login. Your login/passwd will be same login password as you would use with telnet connection.
- Communication is encrypted between two hosts so if someone intercepts your communication he will not be able to use it.
|
| Copy files from/to remote host |
- ftp hostname
- ftp expects you to enter your username/passwd or if it is ftp only account it will require ftp account password .
- put , mput (multipleput) command is used to transfer files to remote host.
- get , mget (multipleput) command is used to transfer files from remote host.
- ftp allows some limited number of commands to be executed at ftp> prompt & summary of ftp command can be found by using ? at ftp> prompt
|
| Securely copy files from/to remote host |
sftp username@hostname:remotefile localfile Communication is encrypted between two hosts. |
| Test the tcp/ip connectivity between two hosts |
- ping hostname
- If you can ping a host the host is reachable from the machine that you are using .
- Router/firewall configuration may prevent ping to succeed .
|
| Backup and Restore |
|
| backup and restore using tar , TApeaRchive |
- tar tvf filename.tar — View the table of content of a tar archive
- tar xvf filename.tar — Extract content of a tar archive
- tar cvf filename.tar file1 file2 file3 — Create a tar archive called filename.tar using file1, file2,file3 .
- tar can’t copy the special files , device files .Not suitable for taking root backup.
|
| backup and restore using cpio , CopyInputOutput |
- cpio is mostly used in conjunction with other commands to generate a list of files to be copied :
#ls | cpio -o > /dev/rmt/c0t0d0 — Copy the contents of a directory into a tape archive:
#find . -depth -print | cpio -pd newdir — copy entire directory to other place:
#find . -cpio /dev/rmt/c0t0d0 — Copy files in current directory to a tape
- cpio can copy special files and hence useful in taking root backup containing device file.
|
| Find files , directories |
| find files , directories |
- Find command is used to find the files , directories and to run commands on the list of files thus generated .By default, find does not follow symbolic links.
-
- find . -name *.log -print — Simple find to list log files
- find . -name ‘*.log’ -exec rm {} \; — Simple find to find log files and delete them .
- find accepts a long list of options to find the files based on different parameters such as create time , modified time , of certain size etc. Please refer to man find for more option.
|