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SSH Commands

Your Bluehost Account includes SSH access. This is a list of common commands that you might use.

Common SSH Commands or Linux Shell Commands

CommandsDescription
catPrint file contents to the screen
cat filename.txtCat the contents of filename.txt to your screen
cd -Change directory
cd ..Go up a directory
cd /usr/local/apacheGo to /usr/local/apache/ directory
cd ~Go to your home directory
cp -a /home/burst/new_design/* /home/burst/public_html/Copies all files, retaining permissions form one directory to another.
cpCopy a file
cp filename filename.backupCopies filename to filename.backup
duShows disk usage.
du -shShows a summary, in human-readble form of total disk space
used in the current directory, including subdirectories.
du -sh *Same thing goes with (du -sh), but for each file and directory.
This is helpful when finding large files taking up space.
fileAttempts to guess what type of file a file is by looking at it's content.
file*Prints out a list of all files/directories in a directory
find * -type d|xargs -i cp --verbose php.ini {}Copies your php.ini file into all directories recursively.
grepLooks for patterns in files
grep -v root /etc/passwdShows all lines that do not match root
grep root /etc/passwdShows all matches of root in /etc/passwd
killTerminate a system process
kill : 9 PID EGkill -9 431
kill PID EGkill 10550
Use top or ps ux to get system PIDs (Process IDs)
lastShows who logged in and when
last -20Shows only the last 20 logins
last -20 -aShows last 20 logins, with the hostname in the last field
lnCreate's "links" between files and directories
ln -s /home/username/tmp/webalizer webstatsNow you can display http://www.yourdomain.com/webstats to show your webalizer stats online.
You can delete the symlink (webstats) and it will not delete the original stats on the server.
lsList files/directories in a directory, comparable to dir in windows/dos.
ls -alShows all files (including ones that start with a period),
directories, and details attributes for each file.
moreLike cat, but opens the file one screen at a time rather than all at once
more /etc/userdomainsBrowse through the userdomains file.
hit Space to go to the next page, q to quit
netstatShows all current network connections.
netstat -anShows all connections to the server, the source and destination ips and ports.
netstat -rnShows routing table for all ips bound to the server.
picoFriendly, easy to use file editor
pico /home/burst/public_html/index.htmlEdit the index page for the user's website.
psps is short for process status, which is similar to the top command.
It's used to show currently running processes and their PID.
A process ID is a unique number that identifies a process,
with that you can kill or terminate a running program on your server (see kill command).
ps auxShows all system processes
ps aux --forestShows all system processes like the above but organizes in a hierarchy that's very useful!
ps U usernameShows processes for a certain user
rmDelete a file
rm filename.txtDeletes filename.txt, will more than likely ask if you really want to delete it
rm -f filename.txtDeletes filename.txt, will not ask for confirmation before deleting.
rm -rf tmp/Recursively deletes the directory tmp, and all files in it, including subdirectories.

**Be extremely careful with using rm. If used improperly you can end up deleting important content that can never be recovered without a restore.

 
tailLike cat, but only reads the end of the file
tail -f /var/log/messagesWatch the file continuously, while it's being updated
tail /var/log/messagesSee the last 20 (by default) lines of /var/log/messages
tail -200 /var/log/messagesPrint the last 200 lines of the file to the screen
topShows live system processes in a nice table, memory information, uptime,
and other useful info.
This is excellent for managing your system processes,
resources and ensure everything is working fine and your server isn't
bogged down.

top
Shift + M to sort by memory usage
Shift + P to sort by CPU usage
touchCreate an empty file
touch /home/burst/public_html/404.html                                    Create an empty file called 404.html in the directory /home/burst/public_html/
viAnother editor, tons of features
vi /home/burst/public_html/index.htmlEdit the index page for the user's website.
wShows who is currently logged in and where they are logged in from.
wc -l filename.txtTells how many lines are in filename.txt
wcword count


EG:

PID TTY TIME COMMAND
10550 pts/3 0:01 /bin/csh
10574 pts/4 0:02 /bin/csh
10590 pts/4 0:09 APP

Each line represents one process, with a process being loosely defined as a running instance of a program. The column headed PID (process ID) shows the assigned process numbers of the processes. The heading COMMAND shows the location of the executed process.

Putting commands together

Often you will find that you need to use different commands on the same line.
Here are some examples.

  • The | character is called a pipe, it takes date from one program and pipes it to another.
  • > means create a new file, overwriting any content already there.
  • >> means tp append data to a file, creating a new one if it does not already exist.
  • < send input from a file back into a command.
  • grep User /usr/local/apache/conf/httpd.conf | more - This will dump all lines that match User from the httpd.conf, then print the results to your screen one page at a time.
  • last -a > /root/lastlogins.tmp - This will print all the current login history to a file called lastlogins.tmp in /root/
  • netstat -an | grep :80 | wc -l - Show how many active connections there are to apache (httpd runs on port 80)
  • mysqladmin processlist | wc -l  - Show how many current open connections there are to mysql
  • mysqldump -u username -p dbname > file.sql - MySQL Dump
  • mysql -u username -p database_name <file.sql - Importing MySQL database
  • tail -10000 /var/log/exim_mainlog | grep domain.com | more - This will grab the last 10,000 lines from /var/log/exim_mainlog, find all occurrences of domain.com (the period represents 'anything', comment it out with a so it will be interpreted literally), then send it to your screen page by page.
  • tar -zxvf file.tar.gz  - UnTAR file
  • which [perl]  -  Finding path to [perl]