El sgte. Listado Recopilado por ahi, nos muestra los 50 comandos mas comunes de UNIX/Linux
Esto no es una lista exhaustiva, por cualquier medio, pero esto debe darle una idea y ayuda a algunos de los comandos de Linux más comunes.
1. Ejemplos Comando TAR
Crear nuevo Archivo tar.
$ tar cvf archive_name.tar dirname/
Extraer desde un Archivo TAR.
$ tar xvf archive_name.tar
Ver contenido de un Archivo TAR
$ tar tvf archive_name.tar
2. Ejemplos Comando GREP
Buscar una cadena determinada en un archivo (case sensitive)
$ grep -i "the" demo_file
Imprimir la línea corresponde, junto con las 3 líneas después de él.
$ grep -A 3 -i "example" demo_text
Buscar una cadena dada en todos los archivos de forma recursiva
$ grep -r "example" *
3. Ejemplos Comando FIND
Buscar Archivos usando el nombre del Archivo ( case in-sensitve find)
# find -iname "MyCProgram.c"
Ejecutar comandos en archivos encontrados por find
$ find -iname "MyCProgram.c" -exec md5sum {} \;
Buscar archivos vacios en directorio personal
# find ~ -empty
4. Ejemplos Comando SSH
Loguearse en host remoto
ssh -l jsmith remotehost.example.com
Debug cliente ssh
ssh -v -l jsmith remotehost.example.com
Mostrar Version Cliente SSH
$ ssh -V OpenSSH_3.9p1, OpenSSL 0.9.7a Feb 19 2003
5. Ejemplos Comando SED
Cuando se copia un archivo de DOS a Unix, se puede encontrar \ r \ n al final de cada línea.En este ejemplo se convierte el formato de archivo de DOS para el formato de archivo de Unix con el comando sed.
$sed 's/.$//' filename
Imprimir Archivo en orden inverso
$ sed -n '1!G;h;$p' test.txt
Añadir numero de linea a todos las lineas no vacias en un archico
$ sed '/./=' test.txt | sed 'N; s/\n/ /'
6. Ejemplos Comando AWK
Remover lineas duplicadas usando awk
$ awk '!($0 in array) { array[$0]; print }' temp
imprimir todas las lineas de /etc/passwd con el mismo uid y gid
$awk -F ':' '$3==$4' passwd.txt
imprimir campo especifico de un archivo.
$ awk '{print $2,$5;}' employee.txt
7. Ejemplos Comando VIM
ir a la linea 143 del archivo
$ vim +143 filename.txt
Ir a la primera coincidencia espceficada
$ vim +/search-term filename.txt
Abrir archivo como solo lectura.
$ vim -R /etc/passwd
8. Ejemplos Comando DIFF
ignorar espacios en blanco mientras se compara
# diff -w name_list.txt name_list_new.txt 2c2,3 < John Doe --- > John M Doe > Jason Bourne
9. Ejemplos Comando SORT
Ordenar Archivo de forma ascendente
$ sort names.txt
Ordenar en forma descendete
$ sort -r names.txt
Ordenar passwd por el 3 campo
$ sort -t: -k 3n /etc/passwd | more
10. Ejemplos Comando EXPORT
ver variables de entorno relacionadas a ""
$ export | grep ORACLE declare -x ORACLE_BASE="/u01/app/oracle" declare -x ORACLE_HOME="/u01/app/oracle/product/10.2.0" declare -x ORACLE_SID="med" declare -x ORACLE_TERM="xterm"
Exportar una variable de entorno
$ export ORACLE_HOME=/u01/app/oracle/product/10.2.0
11. Ejemplos Comando xargs
Copiar todas las imagenes a un disco externo
# ls *.jpg | xargs -n1 -i cp {} /external-hard-drive/directory
Buscar todas las imagenes jpg y archivarlas
# find / -name *.jpg -type f -print | xargs tar -cvzf images.tar.gz
Bajar todas las url proporcionadas en un archivo lista
# cat url-list.txt | xargs wget –c
12. Ejemplos Comando LS
Mostrar peso o tamaño de archivo de forma entendible por el humano
$ ls -lh -rw-r----- 1 ramesh team-dev 8.9M Jun 12 15:27 arch-linux.txt.gz
ordenar archivos en base al ultimo modificado
$ ls -ltr
Visual Classification of Files With Special Characters Using ls -F
$ ls -F
13. Comando PWD
pwd imprime el directorio de trabajo
14. Ejemplo Comando CD
Usar “cd -” para cambiar entre los ultimos 2 directorios
15. Ejemplos Comando GZIP
crear gzip
$ gzip test.txt
descomprimir archivo gz
$ gzip -d test.txt.gz
Display compression ratio of the compressed file using gzip -l
$ gzip -l *.gz
compressed uncompressed ratio uncompressed_name
23709 97975 75.8% asp-patch-rpms.txt
16. Ejmplos Comando bzip2
To create a *.bz2 compressed file:
$ bzip2 test.txt
To uncompress a *.bz2 file:
bzip2 -d test.txt.bz2
17. Ejemplo Comando unzip
Extraer archivo .zip
$ unzip test.zip
Ver el contenido de un archivo .zip:
$ unzip -l jasper.zip
Archive: jasper.zip
Length Date Time Name
-------- ---- ---- ----
40995 11-30-98 23:50 META-INF/MANIFEST.MF
32169 08-25-98 21:07 classes_
15964 08-25-98 21:07 classes_names
10542 08-25-98 21:07 classes_ncomp
18. Ejemplo Comando SHUTDOWN
Apagar inmediatamente.
# shutdown -h now
Apagar despues de r 10 minutos.
# shutdown -h +10
Reiniciar el sistema con shutdown
# shutdown -r now
Forzar al sistema a un chequeo
# shutdown -Fr now
19. Ejemplos Comando FTP
Both ftp and secure ftp (sftp) has similar commands. To connect to a remote server and download multiple files, do the following.
$ ftp IP/hostname ftp> mget *.html
To view the file names located on the remote server before downloading, mls ftp command as shown below.
ftp> mls *.html - /ftptest/features.html /ftptest/index.html /ftptest/othertools.html /ftptest/samplereport.html /ftptest/usage.html
20. Ejemplo Comado crontab
View crontab entry for a specific user
# crontab -u john -l
Schedule a cron job every 10 minutes.
*/10 * * * * /home/ramesh/check-disk-space
21.Ejemplo Comando services
Service command is used to run the system V init scripts. i.e Instead of calling the scripts located in the /etc/init.d/ directory with their full path, you can use the service command.
Check the status of a service:
# service ssh status
Check the steatus of all the services.
service --status-all
Restart a service.
# service ssh restart
22. Ejemplo comando PS
ps command is used to display information about the processes that are running in the system.
While there are lot of arguments that could be passed to a ps command, following are some of the common ones.
To view current running processes.
$ ps -ef | more
To view current running processes in a tree structure. H option stands for process hierarchy.
$ ps -efH | more
23. Ejemplo Comando FREE
This command is used to display the free, used, swap memory available in the system.
Typical free command output. The output is displayed in bytes.
$ free
total used free shared buffers cached
Mem: 3566408 1580220 1986188 0 203988 902960
-/+ buffers/cache: 473272 3093136
Swap: 4000176 0 4000176
If you want to quickly check how many GB of RAM your system has use the -g option. -b option displays in bytes, -k in kilo bytes, -m in mega bytes.
$ free -g
total used free shared buffers cached
Mem: 3 1 1 0 0 0
-/+ buffers/cache: 0 2
Swap: 3 0 3
If you want to see a total memory ( including the swap), use the -t switch, which will display a total line as shown below.
ramesh@ramesh-laptop:~$ free -t
total used free shared buffers cached
Mem: 3566408 1592148 1974260 0 204260 912556
-/+ buffers/cache: 475332 3091076
Swap: 4000176 0 4000176
Total: 7566584 1592148 5974436
24. Ejemplo Comando TOP
top command displays the top processes in the system ( by default sorted by cpu usage ). To sort top output by any column, Press O (upper-case O) , which will display all the possible columns that you can sort by as shown below.
Current Sort Field: P for window 1:Def Select sort field via field letter, type any other key to return a: PID = Process Id v: nDRT = Dirty Pages count d: UID = User Id y: WCHAN = Sleeping in Function e: USER = User Name z: Flags = Task Flags ........
To displays only the processes that belong to a particular user use -u option. The following will show only the top processes that belongs to oracle user.
$ top -u oracle
25.Ejemplo Comando DF
Displays the file system disk space usage. By default df -k displays output in bytes.
$ df -k Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 29530400 3233104 24797232 12% / /dev/sda2 120367992 50171596 64082060 44% /home
df -h displays output in human readable form. i.e size will be displayed in GB’s.
ramesh@ramesh-laptop:~$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda1 29G 3.1G 24G 12% / /dev/sda2 115G 48G 62G 44% /home
Use -T option to display what type of file system.
ramesh@ramesh-laptop:~$ df -T Filesystem Type 1K-blocks Used Available Use% Mounted on /dev/sda1 ext4 29530400 3233120 24797216 12% / /dev/sda2 ext4 120367992 50171596 64082060 44% /home
26.Ejemplo comando PS
Use kill command to terminate a process. First get the process id using ps -ef command, then use kill -9 to kill the running Linux process as shown below. You can also use killall, pkill, xkill to terminate a unix process.
$ ps -ef | grep vim ramesh 7243 7222 9 22:43 pts/2 00:00:00 vim $ kill -9 7243
27. Ejemplo comando RM
Get confirmation before removing the file.
$ rm -i filename.txt
It is very useful while giving shell metacharacters in the file name argument.
Print the filename and get confirmation before removing the file.
$ rm -i file*
Following example recursively removes all files and directories under the example directory. This also removes the example directory itself.
$ rm -r example
28. Ejemplo Comando CP
Copy file1 to file2 preserving the mode, ownership and timestamp.
$ cp -p file1 file2
Copy file1 to file2. if file2 exists prompt for confirmation before overwritting it.
$ cp -i file1 file2
29.Ejemplo Comando MV
Rename file1 to file2. if file2 exists prompt for confirmation before overwritting it.
$ mv -i file1 file2
Note: mv -f is just the opposite, which will overwrite file2 without prompting.
mv -v will print what is happening during file rename, which is useful while specifying shell metacharacters in the file name argument.
$ mv -v file1 file2
30. Ejemplo Comando CAT
You can view multiple files at the same time. Following example prints the content of file1 followed by file2 to stdout.
$ cat file1 file2
While displaying the file, following cat -n command will prepend the line number to each line of the output.
$ cat -n /etc/logrotate.conf
1 /var/log/btmp {
2 missingok
3 monthly
4 create 0660 root utmp
5 rotate 1
6 }
31. Ejemplo Comando MOUNT
To mount a file system, you should first create a directory and mount it as shown below.
# mkdir /u01 # mount /dev/sdb1 /u01
You can also add this to the fstab for automatic mounting. i.e Anytime system is restarted, the filesystem will be mounted.
/dev/sdb1 /u01 ext2 defaults 0 2
32. Ejemplo Comando CHMOD
chmod command is used to change the permissions for a file or directory.
Give full access to user and group (i.e read, write and execute ) on a specific file.
$ chmod ug+rwx file.txt
Revoke all access for the group (i.e read, write and execute ) on a specific file.
$ chmod g-rwx file.txt
Apply the file permissions recursively to all the files in the sub-directories.
$ chmod -R ug+rwx file.txt
33. Ejemplo Comando CHOWN
chown command is used to change the owner and group of a file. \
To change owner to oracle and group to db on a file. i.e Change both owner and group at the same time.
$ chown oracle:dba dbora.sh
Use -R to change the ownership recursively.
$ chown -R oracle:dba /home/oracle
34. Ejemplo Comando PASSWD
Change your password from command line using passwd. This will prompt for the old password followed by the new password.
$ passwd
Super user can use passwd command to reset others password. This will not prompt for current password of the user.
# passwd USERNAME
Remove password for a specific user. Root user can disable password for a specific user. Once the password is disabled, the user can login without entering the password.
# passwd -d USERNAME
35. Ejemplo Comando MKDIR
Following example creates a directory called temp under your home directory.
$ mkdir ~/temp
Create nested directories using one mkdir command. If any of these directories exist already, it will not display any error. If any of these directories doesn’t exist, it will create them.
$ mkdir -p dir1/dir2/dir3/dir4/
36. Ejemplo comando IFCONFIG
Use ifconfig command to view or configure a network interface on the Linux system.
View all the interfaces along with status.
$ ifconfig -a
Start or stop a specific interface using up and down command as shown below.
$ ifconfig eth0 up $ ifconfig eth0 down
37. Ejemplo Comando UNAME
Uname command displays important information about the system such as — Kernel name, Host name, Kernel release number,
Processor type, etc.,
Processor type, etc.,
Sample uname output from a Ubuntu laptop is shown below.
$ uname -a Linux john-laptop 2.6.32-24-generic #41-Ubuntu SMP Thu Aug 19 01:12:52 UTC 2010 i686 GNU/Linux
38. Ejemplo comando WHEREIS
When you want to find out where a specific Unix command exists (for example, where does ls command exists?), you can execute the following command.
$ whereis ls ls: /bin/ls /usr/share/man/man1/ls.1.gz /usr/share/man/man1p/ls.1p.gz
When you want to search an executable from a path other than the whereis default path, you can use -B option and give path as argument to it. This searches for the executable lsmk in the /tmp directory, and displays it, if it is available.
$ whereis -u -B /tmp -f lsmk lsmk: /tmp/lsmk
39. Ejemplo Comando WHATIS
Whatis command displays a single line description about a command.
$ whatis ls ls (1) - list directory contents $ whatis ifconfig ifconfig (8) - configure a network interface
40. Ejemplo Comando LOCATE
Using locate command you can quickly search for the location of a specific file (or group of files). Locate command uses the database created by updatedb.
The example below shows all files in the system that contains the word crontab in it.
$ locate crontab /etc/anacrontab /etc/crontab /usr/bin/crontab /usr/share/doc/cron/examples/crontab2english.pl.gz /usr/share/man/man1/crontab.1.gz /usr/share/man/man5/anacrontab.5.gz /usr/share/man/man5/crontab.5.gz /usr/share/vim/vim72/syntax/crontab.vim
41. Ejemplo Comando MAN
Display the man page of a specific command.
$ man crontab
When a man page for a command is located under more than one section, you can view the man page for that command from a specific section as shown below.
$ man SECTION-NUMBER commandname
Following 8 sections are available in the man page.
- General commands
- System calls
- C library functions
- Special files (usually devices, those found in /dev) and drivers
- File formats and conventions
- Games and screensavers
- Miscellaneous
- System administration commands and daemons
For example, when you do whatis crontab, you’ll notice that crontab has two man pages (section 1 and section 5). To view section 5 of crontab man page, do the following.
$ whatis crontab crontab (1) - maintain crontab files for individual users (V3) crontab (5) - tables for driving cron $ man 5 crontab
42. Ejemplo Comando TAIL
Print the last 10 lines of a file by default.
$ tail filename.txt
Print N number of lines from the file named filename.txt
$ tail -n N filename.txt
View the content of the file in real time using tail -f. This is useful to view the log files, that keeps growing. The command can be terminated using CTRL-C.
$ tail -f log-file
43. Ejemplo Comando LESS
less is very efficient while viewing huge log files, as it doesn’t need to load the full file while opening.
$ less huge-log-file.log
One you open a file using less command, following two keys are very helpful.
CTRL+F – forward one window CTRL+B – backward one window
44. Ejemplo Comando SU
Switch to a different user account using su command. Super user can switch to any other user without entering their password.
$ su - USERNAME
Execute a single command from a different account name. In the following example, john can execute the ls command as raj username. Once the command is executed, it will come back to john’s account.
[john@dev-server]$ su - raj -c 'ls' [john@dev-server]$
Login to a specified user account, and execute the specified shell instead of the default shell.
$ su -s 'SHELLNAME' USERNAME
45. Ejemplo Comando MYSQL
mysql is probably the most widely used open source database on Linux. Even if you don’t run a mysql database on your server, you might end-up using the mysql command ( client ) to connect to a mysql database running on the remote server.
To connect to a remote mysql database. This will prompt for a password.
$ mysql -u root -p -h 192.168.1.2
To connect to a local mysql database.
$ mysql -u root -p
If you want to specify the mysql root password in the command line itself, enter it immediately after -p (without any space).
46. Ejemplo Comando YUM
To install apache using yum.
$ yum install httpd
To upgrade apache using yum.
$ yum update httpd
To uninstall/remove apache using yum.
$ yum remove httpd
47. Ejemplo Comando RPM
To install apache using rpm.
# rpm -ivh httpd-2.2.3-22.0.1.el5.i386.rpm
To upgrade apache using rpm.
# rpm -uvh httpd-2.2.3-22.0.1.el5.i386.rpm
To uninstall/remove apache using rpm.
# rpm -ev httpd
48. Ejemplo Comando PING
Ping a remote host by sending only 5 packets.
$ ping -c 5 gmail.com
49. Ejemplo Comando DATE
Set the system date:
# date -s "01/31/2010 23:59:53"
Once you’ve changed the system date, you should syncronize the hardware clock with the system date as shown below.
# hwclock –systohc # hwclock --systohc –utc
50. Ejemplo Comando WGET
The quick and effective method to download software, music, video from internet is using wget command.
$ wget http://prdownloads.sourceforge.net/sourceforge/nagios/nagios-3.2.1.tar.gz
Download and store it with a different name.
$ wget -O taglist.zip http://www.vim.org/scripts/download_script.php?src_id=7701
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