Basic linux commands
By,
tha.suresh
jemenisuresh@gmail.com
Kanchi Lug Member

LIST...
● ls [options] [file|directory]
●
-l
● will output the files and directories in long list
format.
-s, --size
print the size of each file, in blocks
-S sort by file size
-a, --all
do not ignore entries starting with .

Examble for “ls”
● arul@arul-desktop:~$ ls -l
● total 9692
● drwxr-xr-x 2 arul arul 4096 2009-10-
17 22:12 Desktop
● drwxr-xr-x 2 arul arul 4096 2009-10-
17 22:35 Documents
● drwxr-xr-x 2 arul arul 4096 2009-10-
17 17:58 event

● ls list all files
● ls -l list all files with details
● ls *.gif list gif files
● ls *.gif -l list gif files with details
● ls | wc -l count all files
● ls *.gif | ws -l count gif files
● (wc = word count)

COPY...
● cp [OPTION]... SOURCE DEST
● cp
is the Linux copy command, this shell
command is used to copy files|directories from
one location on the filesystem to another.

options.
● -f, --force
● if an existing destination file cannot be
opened, remove it and try again
● -i, --interactive
● prompt before overwrite
● -R, -r, --recursive
● copy directories recursively

● cp *.txt text
● It will copy all files ending in .txt into the text
directory.
●
To copy a file to your home directory:
cp /usr/local/doc/ue.txt $HOME
This copies the file ue.txt to your home directory

● To copy a file to the parent directory:
● cp mail.txt ..
● This copies the file mail.txt to the directory
immediately above the current working
directory.

f, --force if an existing destination file cannot be opened,
-
remove it and try again
• -i, --interactive prompt before overwrite
• -l, --link link files instead of copying.
• -p same as --preserve=mode,ownership,timestamps
• -R, -r, --recursive copy directories recursively
• -s, --symbolic-link make symbolic links instead of copying
• -u, --update copy only when the SOURCE file is newer than
the destination file or when the destination file is missing
• -v, --verbose explain what is being done

MOVE....
● mv [OPTION]... [-T] SOURCE DEST
● the Linux terminal command to move files|
directories. Like the cp command, but deletes
the original source.

REMOVE...
● rm -f [file]
● option is if you are wanting to force a file to
be removed
● rm -r files
● (recursive remove) Remove files,
directories, and their subdirectories

TOUCH....
● arul@arul-desktop:~/Desktop$ ls
● Home.desktop ShellIntro.pdf su
trash.desktop
● arul@arul-desktop:~/Desktop$ touch new
new1 new2
● arul@arul-desktop:~/Desktop$ ls
● abc Home.desktop new new1 new2
ShellIntro.pdf su trash.desktop zxc

CAT...
● The Linux cat command is the Unix command
to list a file’s contents onto your screen, or pass
via pipeline to use with other Linux commands.
The cat command comes from the word
concatenate.

● arul@arul-desktop:~/Desktop$ cat new
● arul@arul-desktop:~/Desktop$ vim new
● arul@arul-desktop:~/Desktop$ cat new
● sure
● arul
● shrini

mkdir
● The Linux command mkdir is used to make
directories in Linux.
● mkdir - make directories
●

Example
● arul@arul-desktop:~/Desktop$ ls
● abc Home.desktop new new1 new2
ShellIntro.pdf su trash.desktop zxc
● arul@arul-desktop:~/Desktop$ mkdir comm
● arul@arul-desktop:~/Desktop$ ls
● abc comm Home.desktop new new1
new2 ShellIntro.pdf su trash.desktop zxc

grep
grep [OPTIONS] PATTERN [FILE...]
● The Linux grep command is used to extract
lines of data from files
●
arul@arul-desktop:~/Desktop$ grep sure new
sure
arul@arul-desktop:~/Desktop$ grep s new
sure
shrini

WORD COUNT...
● wc counts the characters,lines,words in a file.
● Options:
● -c output char., count
● -l output lines count
● -w output words count

Example
● wc -w linux.txt
● 34
● Display the word count for linux.txt
● Defult: -clw

WHO AM I
● Find which user is loged
shrinivasan@shrinivasan-laptop:~$ whoami
shrinivasan

DATE
● For display the today's date.
● Date prints the systems time and date.
● shrinivasan@shrinivasan-laptop:~$ date
● Sun Oct 18 13:46:29 IST 2009

CALENDAR..
● Cal prints an ASCII calendar of the current
month.
● Cal display the calendar
● shrinivasan@shrinivasan-laptop:~$ cal
October 2009
Su Mo Tu We Th Fr Sa
1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31

EXAMPLE
● shrinivasan@shrinivasan-laptop:~$ cal 12 1988
● December 1988
● Su Mo Tu We Th Fr Sa
1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31

At command
● shrinivasan@shrinivasan-laptop:~$ at 13:57
● warning: commands will be executed using /bin/
sh
● at> echo "hello" > hai
● at> <EOT>
shrinivasan@shrinivasan-laptop:~$ touch hai
●
shrinivasan@shrinivasan-laptop:~$ cat hai
hello

Ps
● ps - report a snapshot of the current processes
● To see every process on the system using BSD
syntax:
● ps -ax
● ps -axu

EXAMPLE
● shrinivasan@shrinivasan-laptop:~$ ps -axu
●
Warning: bad ps syntax, perhaps a bogus '-'? See http://procps.sf.net/faq.html
●
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
●
root 1 0.0 0.0 3084 1888 ? Ss 12:21 0:01 /sbin/init
●
root 2 0.0 0.0 0 0? S< 12:21 0:00 [kthreadd]
●
root 3 0.0 0.0 0 0? S< 12:21 0:00 [migration/0]
●
root 4 0.0 0.0 0 0? S< 12:21 0:00 [ksoftirqd/0]
●
root 5 0.0 0.0 0 0? S< 12:21 0:00 [watchdog/0]
●
root 6 0.0 0.0 0 0? S< 12:21 0:00 [events/0]
●
root 7 0.0 0.0 0 0? S< 12:21 0:00 [khelper]
●
root 8 0.0 0.0 0 0? S< 12:21 0:00 [kstop/0]
●
root 9 0.0 0.0 0 0? S< 12:21 0:00 [kintegrityd/0]
●
root 10 0.0 0.0 0 0? S< 12:21 0:00 [kblockd/0]
●
1000 6967 0.0 0.1 8332 3124 ? S 12:55 0:00 /usr/lib/gvfs/gvfs-gphoto2-volume-monitor
●
1000 7253 1.7 2.0 125404 42836 ? S 13:03 1:02 /usr/bin/okular /home/shrini/Desktop/nice_linux_guide.pdf -icon okular -
●
1000 7343 4.2 5.8 246512 120996 ? Sl 13:04 2:30 /usr/lib/openoffice/program/soffice.bin -impress /home/shrini/Desktop/li
●
postfix 10471 0.0 0.0 5792 1684 ? S 13:59 0:00 pickup -l -t fifo -u -c
●
1000 10698 0.0 0.0 2768 1032 pts/1 R+ 14:03 0:00 ps -axu
●

Kill the opretion
●
Kill -9 6967
●
Warning: bad ps syntax, perhaps a bogus '-'? See http://procps.sf.net/faq.html
●
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
●
root 1 0.0 0.0 3084 1888 ? Ss 12:21 0:01 /sbin/init
●
root 2 0.0 0.0 0 0? S< 12:21 0:00 [kthreadd]
●
root 3 0.0 0.0 0 0? S< 12:21 0:00 [migration/0]
●
root 4 0.0 0.0 0 0? S< 12:21 0:00 [ksoftirqd/0]
●
root 5 0.0 0.0 0 0? S< 12:21 0:00 [watchdog/0]
●
root 6 0.0 0.0 0 0? S< 12:21 0:00 [events/0]
●
root 7 0.0 0.0 0 0? S< 12:21 0:00 [khelper]
●
root 8 0.0 0.0 0 0? S< 12:21 0:00 [kstop/0]
●
root 9 0.0 0.0 0 0? S< 12:21 0:00 [kintegrityd/0]
●
root 10 0.0 0.0 0 0? S< 12:21 0:00 [kblockd/0]
●
1000 7253 1.7 2.0 125404 42836 ? S 13:03 1:02 /usr/bin/okular /home/shrini/Desktop/nice_linux_guide.pdf -icon
okular -
●
1000 7343 4.2 5.8 246512 120996 ? Sl 13:04 2:30 /usr/lib/openoffice/program/soffice.bin -impress
/home/shrini/Desktop/li
●
postfix 10471 0.0 0.0 5792 1684 ? S 13:59 0:00 pickup -l -t fifo -u -c
●
1000 10698 0.0 0.0 2768 1032 pts/1 R+ 14:03 0:00 ps -axu
●

TOP..
● shrinivasan@shrinivasan-laptop:~$ top
●
top - 14:15:16 up 1:53, 1 user, load average: 0.74, 0.88, 0.75
●
Tasks: 152 total, 3 running, 149 sleeping, 0 stopped, 0 zombie
●
Cpu(s): 17.2%us, 3.3%sy, 0.0%ni, 79.5%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
● Mem: 2061340k total, 1424900k used, 636440k free, 63056k buffers
● Swap: 1951856k total, 0k used, 1951856k free, 564504k cached
●
● PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
●
3963 shriniva 20 0 349m 135m 28m S 7.9 6.7 9:15.43 firefox-bin
●
3433 root 20 0 356m 268m 6048 R 5.0 13.3 7:27.77 Xorg
●
3916 shriniva 20 0 343m 53m 31m R 3.3 2.7 3:27.88 plasma
●
3966 shriniva 20 0 134m 28m 17m S 2.0 1.4 0:23.26 konsole
●
3944 shriniva 20 0 94168 26m 20m S 0.7 1.3 0:38.21 ktorrent
●
11311 shriniva 20 0 2448 1212 912 R 0.7 0.1 0:00.12 top
● 2657 mysql 20 0 124m 16m 4948 S 0.3 0.8 0:05.77 mysqld
● 4039 shriniva 20 0 678m 52m 14m S 0.3 2.6 0:26.06 java
●
1 root 20 0 3084 1888 564 S 0.0 0.1 0:01.41 init
●
2 root 15 -5 0 0 0 S 0.0 0.0 0:00.00 kthreadd
● 3 root RT -5 0 0 0 S 0.0 0.0 0:00.00 migration/0
● 4 root 15 -5 0 0 0 S 0.0 0.0 0:00.20 ksoftirqd/0
● 5 root RT -5 0 0 0 S 0.0 0.0 0:00.00 watchdog/0
●
6 root 15 -5 0 0 0 S 0.0 0.0 0:00.05 events/0
●

crontab
● # m h dom mon dow command
● 53 14 * 10 * echo"hai" >
/root/shrini/home/hai
● shrinivasan@shrinivasan-laptop:~$ cat hai
● hello

THANK YOU