Oracle DBA - Linux Commands

File Commands

S.No

Command

Comments

1

ls

Directory listing

2

ls -al

Formatted listing with hidden files

3

ls -lt

Sorting the Formatted listing by time modification

4

cd dir

Change directory to dir

5

cd

Change to home directory

6

pwd

Show current working directory

7

mkdir dir

Creating a directory dir

8

cat >file

Places the standard input into the file

9

more file

Output the contents of the file

10

head file

Output the first 10 lines of the file

11

tail file

Output the last 10 lines of the file

12

tail -f file

Output the contents of file as it grows,starting with the last 10 lines

13

touch file

Create or update file

14

rm file

Deleting the file

15

rm -r dir

Deleting the directory

16

rm -f file

Force to remove the file

17

rm -rf dir

Force to remove the directory dir

18

cp file1 file2

Copy the contents of file1 to file2

19

cp -r dir1 dir2

Copy dir1 to dir2;create dir2 if not present

20

mv file1 file2

Rename or move file1 to file2,if file2 is an existing directory

21

ln -s file link

Create symbolic link link to file

Process management

1

ps

To display the currently working processes

2

top

Display all running process

3

kill pid

Kill the process with given pid

4

killall proc

Kill all the process named proc

6

bg

List stopped or background jobs,resume a stopped

job in the background

7

fg

Brings the most recent job to foreground

8

fg n

Brings job n to the foreground

Searching

1

grep pattern file

Search for pattern in file

2

grep -r pattern dir

Search recursively for pattern in dir

3

command | grep pattern

Search pattern in the output of a command

4

locate file

Find all instances of file

5

Find . -name

filename        

Searches in the current directory (represented by a period) and below it, for files and directories with names starting with filename

System Info

1

date

Show the current date and time

2

cal

Show this month's calender

3

uptime

Show current uptime

4

w

Display who is on line

5

whoami

Who you are logged in as

6

finger user

Display information about user

7

uname -a

Show kernel information

8

cat /proc/cpuinfo

Cpu information

9

cat proc/meminfo

Memory information

10

man command

Show the manual for command

11

df

Show the disk usage

12

du

Show directory space usage

13

free

Show memory and swap usage

15

which app

Show which applications will be run by default

Compression

1

tar cf file.tar file

Create tar named file.tar containing file

2

tar xf file.tar

Extract the files from file.tar

3

tar czf file.tar.gz files

Create a tar with Gzip compression

4

tar xzf file.tar.gz

Extract a tar using Gzip

5

tar cjf file.tar.bz2

Create tar with Bzip2 compression

6

tar xjf file.tar.bz2

Extract a tar using Bzip2

7

gzip file

Compresses file and renames it to file.gz

8

gzip -d file.gz

Decompresses file.gz back to file