Perintah yang sering digunakan mengelola server via SSH

OVERVIEW

This article is an introduction to finding your way around your server inSSH. It takes a Day 1 approach to SSH.

• HitEnterorReturnafter every command unless specified otherwise.
• The domainexample.comshould always be replaced with your own domain name.
• Example paths and file names should also be replaced with your own server information.

REQUIREMENTS

This article assumes that:

1. You have enabled an SSH user. This is usuallyrootor a sudo user.
2. You have used Terminal (Mac) or PuTTY (Windows) to log into the server. You should be looking at a command prompt.

If you need help with these steps, please see:Connecting via SSH to your server.

READ ME FIRST

This article is provided as a courtesy. Installing, configuring, and troubleshooting third-party applications is outside the scope of support provided by (mt) Media Temple. Please take a moment to review theStatement of Support.

HOME AND NAVIGATION

When you first log into your server, you will be in your home directory.

• For the root user, this is/root/.

Linux folder structure

Linux uses a nested folder structure to store different files. The top-level directory is considered the root directory, and is designated by/. Folders beneath the root level are separated by slashes. For example, all of your website content is located in/var/www/vhosts/example.com/.

TIP:

Remember that/is not the same as/root/. The/is the root level of the server. You cannot get any higher than that. The home directory for the user called root is/root/.

Common paths:

• /home/00000/domains/example.com/html//var/www/vhosts/example.com/httpdocs/- web document root

• /home/00000/logs//var/www/vhosts/example.com/statistics/logs/- per-domain access and error logs
• /var/www/vhosts/example.com/conf/ - per-domain configuration files

• /home/00000/etc/ - location of php.ini file/etc/ - configuration files
• /etc/init.d/ - software daemon start files

Move into another directory

Use this command to move into a directory:

cd

You can specify the full path from the root of the server:

cd /var/www/vhosts/example.com/conf/

You can type the path from where you are now (leave out the beginning/):

cd downloads/

You can go up a directory level:

cd ..

You can go to your home directory:

cd ~

Where am I?

Working with your server without graphics can take a little getting used to. If you ever need to see exactly which folder you're in, use the following command:

pwd

It stands forprint working directory. You'll see output like this:

/var/www/vhosts/

What's here?

Next, we want to see a list of files and folders in our current directory:

ls -alh

lsis thelistcommand, and-alhmodifies the standard list in three ways.ameans that all files, even hidden files, should be shown.lmeans that the long format is used - it shows things like file size and the date every file was last modified.hmakes the sizes display in convenient units. Here's some sample output:

drwxr-x--- 10 domainuser psaserv 4.0K Oct 20 19:51 . drwxr-xr-x 14 root root 4.0K Aug 17 22:16 .. -rw-r--r-- 1 domainuser psacln 58 May 31 22:49 .htaccess -rw-r--r-- 1 domainuser psacln 2.1K Apr 20 2010 about.php -rw-r--r-- 1 domainuser psacln 907 Feb 25 2010 archive.php drwxr-xr-x 2 domainuser psacln 4.0K Jul 2 16:43 image -rw-r--r-- 1 domainuser psacln 1.9K Mar 5 2010 index.php

FILES

Let's break down the elements of a file that are displayed when you run thels -alhcommand from the previous section.

-rw-r--r-- 1 domainuser psacln 1.9K Mar 5 2010 index.php

• -rw-r--r-- - These are the permissions for this file.rstands for "read,"wstands for "write," andxstands for "execute." The first character is standalone, and the next nine are in groups of three: the first triplet (rw-) applies to the owner, the second (r--) to the group, and the third (r--) to everyone. So, in this example, the owner has read and write access, the group just has read access, and everyone has read access. SeeFile Permissionsfor an in-depth discussion.
• 1- Number of links to this file.
• domainuser- The owner of this file.
• psacln- The group this file belongs to.
• 1.9K- The size of this file.
• Mar 5 2010- The date this file was last modified.
• index.php- The name of this file.

Change permissions, owner, and group

This section shows basic commands for changing the access settings on a file. It is highly recommended that you readFile Permissionsbefore making any changes, so you'll know what kinds of changes are good and what might be a security risk.

To change permissions:

chmod 755 index.php

chmod

is the command.755is a code which tells what kinds of read, write, and execute permissions you want for the file.index.phpis an example - you should replace with your file name.

Quick permissions guide:

7 = Read + Write + Execute

6 = Read + Write

5 = Read + Execute

4 = Read

3 = Write + Execute

2 = Write

1 = Execute

0 = All access denied

First number is for the owner, second for the group, and third for everyone.

To change owner:

chown domainuser index.php

chown

is the command, short for "change owner."domainuseris an example of a possible owner name - you should substitute this with your desired owner name. Note that the owner must exist on the server.index.phpis an example - you should replace with your file name.

To change group:

chgrp psacln index.php

chgrp

is the command, short for "change group."psaclnis an example of a common Plesk group - you should substitute this with your desired group name. Note that the group must exist on the server.

Change owner and group at once:

chown domainuser:psacln index.php

This command is exactly like the previouschownexample, except that the group is also specified, after a colon (:).

Copy file

Use this command to copy a file to a different location (first example), or to the same folder but with a new name (second example):

cp logo.png image/logo.png

cp index.php index.php_old

cp

is the command. The first file listed is the one you want to copy. The second file is the new name for the copied version of the file, including any path information for where the copy should be located. You can use a relative path like in the example above (that is, there is animagefolder inside your current folder already), or you can use a full server path starting with/.

You can also copy an entire folder (along with all subfolders) using-R:

cp -R image/ image2

Move or rename file

The format for the move command is very similar to that for the copy command. Here's an example:

mv logo.png image/logo.png

mvis the basic command. This moveslogo.pnginto theimage/subdirectory.

You can also use it to rename a file:

mv index.php index.php_old

This renamesindex.phptoindex.php_old.

Finally, you can move a folder just as easily as a single file. This example shows how to move the folderimage/up one level (..means "up one level"):

mv image/ ..

Compressing and decompressing a file using zip

Use this command to compress a file:

zip -r archive_name.zip folder_to_compress

Use this command to decompress a file:

unzip archive_name.zip

In these examples,

zip

and

unzip

are the commands. The

-r

option tells the command to work recursively. The

archive_name.zip

listed is the name of the file. Lastly,

folder_to_compress

is the directory you wish to compress.

Rsync

The

rsync

command can be used instead of the cp command, and works on all platforms of linux. Rsync can be used in the same way as cp with added benefits such as file permission and ownership preservation, compression during transfer, and comparison between files for updates to back ups.

rsync -a logo.png images/logo.png

rsync -a index.php index.php_old

rsync

is the command, followed by the '-a' flag which lets the system know to preserve the permissions, ownership, timestamp, and if rsyncing a directory, to do it recursively. The next part, 'logo.png' is the source file followed by the destination for that file to be copied to.

Another use for rsync is the ability to copy files and folders over a network to another server. This can be very helpful if you want to run some back ups, or migrate from one server to another within the (mt) Media Temple network. This first example will show you how to copy the entire document root for example.com to another server using it's SSH login credentials.

rsync -avz example.com user@host:/path/to/destination

When you hit enter, you will be prompted to enter in the password foruseron the remote server. This will move the entire directory,example.comand it's contents over to the destination on the remote server. The options, '-avz' let rsync know that you want to archive the file permissions, ownership, get a verbose readout of what file is being processed, and you would like to compress the files in order to use less bandwidth.

You can also reverse this to download a copy of files from a remote server to your local machine.

rsync -avz user@host:/path/to/source ./

Once again, you will be prompted for the password for the user account on the remote server. This will copy the specified file from the remote server to the current working directory on your local machine.

Create or edit a file

• Create or edit a file:

vi file.html

If this is anewfile, it'll be empty when you open it, and you can start adding content. If this is anexistingfile, you'll see its contents, which you can now edit.

vi tip: Press "i" to enter "insert mode" so you can type and copy/paste. Use the arrow keys to move back and forth in the file. Press "Esc" to exit "insert mode" when you are done modifying the file. Type ":wq" to save and quit.

SeeUnderstanding basic vi (visual editor)for more details.

• Create an empty file (which you can later open for editing):

touch new_file.html

If you use an existing file name, it will instead "touch" that file and update its last-modified date.

Files are created with the owner and group of your SSH user. Once you've created a new file, it's a good idea to runls -alhto make sure its ownership matches the rest of the files in the directory. If not, run thechowncommand from the earlier section.

Read or search within a file

If you need to look through a file, the quickest way to get all the contents on your screen iscat:

cat index.html

<html> <head> <title>Home</title> </head> <body> <p>Hello, world!</p> </body> </html>

However, this can be overwhelming if you have a large file. In that case, you can uselessor| moreto conveniently scroll through the content.lessuses the arrow keys, andmoreuses Enter. Typeqto exit either of them.

less access_log

cat access_log | more

• Search files for a specific phrase:

cat error_log | egrep "permission"

This will list only the lines containing the word "permission."catshows the contents. Next, type the name of the file.|means the output should be filtered through the next command.egrepdoes the search. Your search term should go in quote marks, just in case it has special characters.

Delete file

You can also delete a file using SSH. Be sure you don't need it any more before you delete it.

rm index.php_old

You will receive output like the following:

rm: remove regular file 'index.php_old'?

Typeyconfirm, ornto cancel. If you don't want to be prompted, add-fto the command:

rm -rf index.php_old

Also, if you want to remove an entire directory and all its contents, including subdirectories, add-r. It can become tedious quickly to approve every deletion in a directory, so-fis commonly used.

Please be cautious with therm -rfcommand. It will irreversibly delete a folder and all of the files and subfolders in it.

To make sure you're deleting the right thing, you can always run a list command first. For example:

ls -alh /path/to/unwanted/folder/

Here's the recursive deletion command:

rm -rf /path/to/unwanted/folder/

Disk use

• Total server disk use:

df -h

You will see output like this, with an amount used and a percent used:

Filesystem Size Used Avail Use% Mounted on /dev/vzfs 20G 3.1G 17G 17% / simfs 20G 3.1G 17G 17% /tmp simfs 20G 3.1G 17G 17% /var/tmp

• Show all folder sizes for the current directory recursively, with their sizes:

du -h

If you run this from a high-level directory, it can take a while to complete.

• Show a disk use summary for the current directory:

du -sh

Again, this can take a little while if you're running it in a high-level directory.

• Here's an advancedfindcommand you can run to find files over 10 MB (no variables in this one, just copy and paste):

find / -mount -noleaf -type f -size +10000k -print0 | xargs -0 ls -lhSr | awk '{printf "%*s%sn",7,$5":",$9}'

DV SERVER ADMINISTRATION

Plesk admin password

• Show Pleskadminpassword:

cat /etc/psa/.psa.shadow

MySQL access

The DV server has a simple shortcut for logging into MySQL:

my

Typequitto exit.

If you want to export or import a database, seeExport and import MySQL databases.

Processes and system services

• Show current server processes:

ps -auxf

• Show processes and memory use live:

top

• Start/Stop Services:

/etc/init.d/httpd restart

This example restarts Apache. You can also usestartandstop. SeeRestart Plesk servicesfor a list of services.

• Check Bean Counters for system resource limits (hard and soft limits, failcounts, etc.):

cat /proc/user_beancounters

For an explanation of the results of several of these commands, and for more advanced resource tracking and troubleshooting, consider readingTroubleshooting DV Memory Issues.

Log Files

Log files can tell you a lot about what's happening on your DV server. Log files are generally very long, so you should use one of these commands to sort through them easily:

• Show the most recent 100 lines of the file:

tail -n 100 /var/www/vhosts/example.com/statistics/logs/error_log

• Watch this file live. Interact with your server (by trying to reproduce the error, or navigating your website) while this is running and watch the log file update. UseCTRL-Cto exit.

tail -f /var/www/vhosts/example.com/statistics/logs/access_log

Log locations

• Apache error log for your domain:

/var/www/vhosts/example.com/statistics/logs/error_log

• Statistic log for your domain:

/var/www/vhosts/example.com/statistics/logs/access_log

• Server error log:

/var/log/messages

• Apache error log:

/var/log/httpd/error_log

• MySQL logs:

/var/log/mysqld.log

• Mail logs:

/usr/local/psa/var/log/maillog

• SSH history - just type:

history

• It's normal to have hundreds of failed SSH and FTP connection attempts; it's a reminder that we all need to usestrong passwords.
• Set uplog rotationto keep logs from growing too large.
• The mail logs are great for seeing spam activity and for tracking message delivery/failure. SeeTroubleshooting common issues with emailfor further assistance.

FINAL TIPS

• When you are typing a path or file name, hit "Tab" after the first few letters. If it's the only file or folder matching the letters you've typed, the rest of it will auto-complete.
• Hit the up arrow to scroll back through previous commands - save yourself some typing!
• Always make a backup copy of the working version of a file before editing it.
• qorCTRL-Cusually gets you out of any special mode you might be in.
• If you've encountered an unknown command, type "man" and then the command name to learn more about it. (Example:man ls) This will also show you special options like the-alhoption for the list command.

Tambahan

• Untuk menampilkan file html terbaru 2 hari ini, beserta tanggal dan jamnya:find -mtime -2 -name "*.html" -printf '%Tc %pn'
• Untuk mencari file html yang ada kata-kata "rendang" di dalamnya:grep -r --include=*.html -PHn "rendang"