• passwd (set your password)   
• Backspace and Delete (ensure keys work as you want)
• chmod
• du (display directory sizes)
• fc (history)
• ln (linking files/dirs)
• lsof (list open files)
• xargs (piping file names to a command)
• redirection
• find
• ftp   
• scp (secure copy)
• sftp (secure ftp)
• tar (pack entire filesystem branch into a single file)
• mv branch   
• Compression / Decompression   
• ar (archive program routines in a library)
• df (display file system statistics)
• awk (filter rows by elements)
• apache (web server)
• vi
• C   
• tr   

For safety reasons we do no longer show here the specifications for our machines. Use this link (SEMachines.html) to access the description (access restricted).

Most of our servers belong to a cluster of simulation servers. Find here more information on the basic philosophy behind our simulation servers. For the software please see RAMSES (Research Aids for Modeling and Simulation of Environmental Systems, notably the software layer RASS (RAMSES Simulation Server).

Any hints on the usage of OS X via the Aqua interface are on page Mac Hints - OS X.

OS X is based on Darwin. Similar to Solaris on our Suns, Darwin is a BSD Unix. This web page is for you when you use OS X via the application Terminal. This application is located within your Applications folder within folder Utilities (/Applications/Utilities/Terminal.app). All what you find on this web page should apply to Darwin as well.

RASS has a home page.

Typically working with RASS on a Unix host (Sun or OS X simulation server) goes as follows:

1. You upload first your MDP (Model Definition Program), you wish to run under RASS to the Unix host.

   To this end mount the Unix host, e.g. by afp (formerly called AppleShare). Then create a directory (folder) into which you transfer your MDP by drag and drop. If your MDP requires more than just a program module, simply upload all these files together with the main program module.

   Alternatively you may use scp (secure copy), a sftp client such as VicomSoft FTP Client or ftp client such as Fetch or some other client, which manages to upload the files. Note, however, most ftp clients such as Fetch will most likely change the content of each text file during upload. In some cases this may be ok, in others this may be a problem. Note, that the RASS utilities such as prepare will take care of the file formats. Therefore, for beginners it is recommended to use AppleShare (transfer does not change the content of files) for managing your files on one of our Unix hosts. Finally note, this offers also the advantage of being able to use Alpha to edit the content of files, which reside remotely on the Unix machine.

2. Once all files are uploaded, you have to use a shell to execute the simulation program.

   Login via a secure shell terminal program, e.g. Terminal (OS X standard application) or NiftyTelnet 1.1 SSH r3. After a login you get started by typing the command

           RASSHelp

   Everything else should follow from there.
    

3. Once the simulation is finished you should get an E-mail, which informs you about the fact that the simulation experiment has finished.

   Note, you get the E-mail only if you have installed your MDP correctly, notably asked for sending the E-mails to your ordinary E-Mail address. Otherwise you may have to change the settings, e.g. by using RASS utility setRASSmailto

4. To get the results you can login and inspect them, e.g. use command less to look at the job's protocol, or you may wish to download the result files to your own machine.
   IMPORTANT NOTE: Unless explicitely stated none of our simulation servers does backup data! Thus it is fully your responsibility to ensure that nothing important gets lost.

   It is recommended to use either sftp, scp or afp to accomplish this. Note, if you have generated a stash file during your simulation experiment, you can look at your results interactively from within the RAMSES shell, using the "Post Analysis Session" (note, stash files are simple text files).

5. If you encounter errors and have been executing your MDP locally, you can conveniently display compiler errors in AlphaX (Alpha) and run time errors in the debugger. Displaying of compiler errors on a simulation server is less convenient, since it can't launch AlphaX for you. However, you can still conveniently edit any source code on the simulation server by mounting your home directory via afp.
6. Here some hints on how to use the RASS-OSX debugger. IMPORTANT NOTE: The debugger is only launched if you have linked your code with the debug option -d, i.e. mk -d or mk1 -d .... The current debugger offers some interactivity and can be controlled in the following manner:
   • Activate menus at the top (first letter bold) by <ctrl> + <letter>
   • Navigate within a menu via cursor keys, <return> chooses current menu
   • Typing a capital letter (<shift> + <letter>) chooses the menu command as shown with a apple-shortcut (<apple symbol> + <letter>) (current implementation restriction: only the commands of the data menu are functional)
   • The currently active window is shown with a yellow background. It is the one that receives all keyboard entries (unless they are a menu command)
   • Use <tab> to switch window activation
   • Scroll within the currently active window by <cursor up> or <cursor down>
   • The debugger reads two files: debug.dat and debug.in. The file debug.dat defines all paths needed to access any source code (any row starting with 'M' for any files with extension 'MOD') and for reference information (any row starting with 'R' for files with extension 'MREF'). The file debug.in controls the behavior of the debugger, which is relevant in any batch use. This function is currently not fully implemented, and merely the presence of this file causes the debugger display to terminate by "exit (-1)". Later implementations should allow to control the behavior of the debugger by a sequence of keyboard entries.
7. Relevant compilers are described here:
   • MacMETH
   • epc
   • P1

Note, we have also several other documentations, which should help you to get going with RASS. See our series of "Systems Ecology Reports", notably reports 14, 9, 20, 21, and 23.

Visit the RASS home page for further links and literature.

To learn about Unix commands I recommend to visit
Apple's «Mac OS X Manual Pages»   Excellent!
Learn Unix in 10 minutes
Bash commands
OpenBSD Man Pages
UNIX ON-LINE Man Pages (Solaris)
UNIX ON-LINE Man Pages (by Panagiotis Christias) UNIX ON-LINE Man Pages (by University of Athens) or to type

        man <cmd>

where <cmd> stands for any command you know and you wish to learn more about its use. Click here... for more on this.

Check also your environment variable MANPATH, e.g. by entering

        echo $MANPATH

Ensure it contains all those paths where man pages reside and which you wish to access while using man. In many cases it is sufficient to enter the following line into your invisible ~/.profile file:

        export MANPATH=/usr/share/man:/usr/local/share/man:/usr/local/man:/usr/X11R6/man

The following commands

        cd ; open -a AlphaX .profile

lets you easily edit that file. Alternatively you may add any missing path(s) to file /usr/share/misc/man.conf similar to this:

        ...
        MANPATH /usr/local/share/man
        MANPATH /usr/local/man
        ...

If not empty by system default extend environment variable MANPATH similar to this:

        export MANPATH=$MANPATH:/usr/share/man:/usr/local/share/man:/usr/local/man:/usr/X11R6/man

• passwd
  

  To set or change your password use the command

          passwd

  everything should follow from there. For security reasons (IMIPORTANT!) make sure you follow the ETHZ's password recommendations as described in our Shadow home page under link "Hints on passwords".

• Backspace and Delete
  

  To fix on the fly Backspace resp. delete, type command

          stty erase X 

  where X is the key which should do the delete of the previous char.

  Backspace in MacSamson: Use menu command 'Terminal Settings...' and activate 'DELETE does BACKSPACE'. Then backspace key on Mac keyboard should also behave as desired.

• chmod
  

  Traditionally this command is used to modify the UNIX file access permissions of files and directories. Use man to learn about the command or visit here.

  These days access permissions are defined by ACLs (Access Control List), which define the privileges granted to each user. They are more cumbersome to manage. Learn about currently set ACLs with command

          ls -le
          

  To get rid of inadvertently set ACLs may be difficult and I found the following useful

          sudo echo | sudo chmod -R -E ./*

  to delete all ACLs recursively from the files in the current working directory in cases where everything else failed (Note, command acl may also be useful in this context).

  Note, extended attributes is again something different and should not be confounded with ACLs. They are listed by

          ls -la@
          

  They do not control access permissions, but contain extra information in form of any number of strings attached to any given file. To delete any of them you need command xattr -d and the exact content of individual strings and the syntax of the command to delete one extended attribute is this:

          xattr -d "<extended attribute text>" <pathfilename>

  Ex.:

          xattr -d "com.apple.metadata:kMDItemWhereFroms" ~/Documents/MyFile.txt

  On older OS X systems confusingly the xattr command has no man page, but it gives usage information with the -h flag. OS X 10.5.x (Leopard) issued warning before opening a freshly downloaded file makes use of extended attributes. You can prevent this with a command such as

          xattr -d com.apple.quarantine <downloaded_file>

  Executing above using an AppleScript allows to automatically delete the hereby used extended quarantine attributes. Attach such an AppleScript as a folder action to the Downloads folder (Lift the Leopard download quarantine).

  Find an excellent discussion of permissions and attributes at File permissions and attributes.

  ---

• du (disk usage)
  The following command

  	du -sh *

  lists you the size of the directories in the current working directory and

  	du -sh

  gives you the total size occupied by the current working directory.

  	du -sh Public

  gives you the total size occupied by the designated directory, here Public.

• fc (history)
  

  To geta list of all commands you recently used, enter

  	fc -ln

  This gives you a history without numbers for easy copy pasting. Note the mere option -n would open a file with vi and is usually not what you want. Unix Manual Page for fc

  Of course to get just some of the most recently used commands, simply use cursor <up> and <down> keys.

  ---

• ln (linking files/dirs)
  

  Create a symbolic link, for instance to a directory, by entering e.g.

  	     ln -s MyDir linkToMyDir

  The first argument MyDir is the actual directory holding any file physically. The second argument linkToMyDir ist the symbolic link. Note, the symbolic link behaves exactly as its real counterpart.

  A symbolic link looks like this in a directory listing. E.g. ls -l in my home directory may return following result after I have defined above symbolic link:

  	     /home/afischli/linkToMyDir -> /home/data1/MyDir
  	

  Check it out.

  ---

• lsof (list open files)
  

  This command can be used for many purposes, one of them being to learn about internet traffic. The latter may be useful while debugging firewall settings. E.g. the command

  	     lsof -nP | grep TCP

  lists all current TCP connections.

  ---

• xargs (piping file names to a command)
  

  Some commands require an argument with file names. This argument can either be a specific file or a list of operands, i.e. list of files. E.g. grep is a command which can be used in such a way:

  	     grep myfiles todir

  Some of these commands still use standard input or standard output. Thus it is not trivial to use a command which generates a list of files on standard output and to feed that list to another command which requires a list of files. This is exactly where xargs comes handy. E.g.

  	     ls | xargs grep "pattern"

  The first command generates a list of files. xargs feeds those files as operands to the subsequent command grep.

  ---

• redirection (redirecting standard output, error etc.)
  

  In addition to the usual redirections of standard input and output using <, >, <<, or >>, respectively, you can also redirect standard error. Unfortunately the syntax differs greatly from shell to shell. Here some examples, which should get you going quickly:

  Merge standard output and error onto standard output:

  • csh or tcsh:

    	     task |& tee filename 

  • bash:

    	     task 2>&1 | tee filename 

    Note that the order of redirections is significant. For example, the command

    	     task > dirlist 2>&1 

    directs both standard output and standard error to the file dirlist, while the command

    	     task 2>&1 > dirlist 

    directs only the standard output to file dirlist, because the standard error was duplicated as standard output before the standard output was redirected to dirlist.

  Redirect standard output and standard error onto 2 different files named filename1 and filename2:

  • csh, tcsh, or bash:

    	     (task > filename1) >& filename2

• find
  

  To find a file in the file hierarchy starting from current directory, type a find command similar to this example

  	find . -name "*.R" -print |& grep "Permission denied" -v

  with a bash shell modify the command to

  	find . -name "*.R" -print 2>&1 | grep "Permission denied" -v

  A more robust alternative searching for all files with extension .pub and string rsa in the file name on the entire machine:

  	( find / -name "*.pub" -print | xargs  grep -nl "rsa" ) 2> /dev/null

  where "*.R" can be of course any other pattern to match the file names you are looking for. The pipe serves the purpose to suppress all those error messages where you don't have permission to read in the directory, e.g. if you search from the root, i.e. everywhere, this is likely to generate lots of output of little interest. Should you really wish to search really everywhere, you need to use sudo.

  To find a file by its inode, e.g. when having repaired a disk using fsck or application "Disk Utility" (in Mac OS X from folder "/Applications/Utilities/"):

          find / -inum 160014 2>&1 | grep -v "Permission denied"

  It may then be useful to cross-check the found files by using a command similar to the following:

          stat -f "%i" "/Volumes/HD/uaf/Documents/SysInfos/SysInfos-Install Logs o/Disk Reports/DiskUsage Cube 2008.08.15.xls"

  which returns the inode number.

  To search for applications or commands it is easier to use commands like which and whereis.

  ---

• ftp
  For security reasons ftp is used less and less. Yet, to access a remote anonymous ftp server, it is still a most useful service. In general it is recommended to use it with option -n to give you maximum flexibility. Ex.:

  	% ftp -n
  	ftp> open baikal.ethz.ch <- or whichever remote host you wanna connect to
  	Connected to baikal.ethz.ch.
  	220 baikal FTP server (Version 6.9 Fri Feb 5 17:31:11 MET 1993) ready.
  	ftp> user amueller  <- or whoever user you wanna login as
  	331 Password required for amueller.
  	Password:  <- enter your password as requested
  	230 User amueller logged in.
  	ftp> cd forclim
  	...
  	

  Here you can use commands like cd, ls etc. to navigate on the machine to which you are connected. To actually transfer files use get or put. With put files will arrive, with get files will come from the current working directory. To access other files preceed them with a path relative to the current working directory. To terminate a ftp session use close to disconnect from the remote host and/or quit to leave the entire ftp session.

  Unix to Unix ftp works fine with all types of files, however, note, permissions are not transferred and need to be set anew on the target machine. Transfer from/to PCs depends on the software used. IBM PC machines or Macintosh ftp servers tend to behave too intelligently and change file contents. Be careful and make sure ftp parameters are set as you really want them, or files contents may get corrupted. This link contains lots of useful information when working with our main file server, i.e. atlantis.ethz.ch.

  See also sftp and scp for alternatives to ftp (more secure!)

  ---

• scp
  You can use scp while logged in by a ssh conncetion. This is more secure than ftp and highly recommended. E.g. you wish to transfer an entire directory named 'FC' from your OS X Mac (IP-name semac01.ethz.ch) into the current working directory on the Sun (e.g. huron.ethz.ch). Start typing

  	% scp -r semac01:
  	

  and drag-drop with the mouse the directory FC right after the typed column. The command line should look similar to this

  	% scp -r semac01:/Volumes/HD2/Sim/RMS/Work/FC
  	

  Finally type a blank and a period for the current directory:

  	% scp -r semac01:/Volumes/HD2/Sim/RMS/Work/FC .
  	

  Then the command line is complete and you can hit return. Note, in this example the full path and file name for the directory on your Mac was /HD2/Sim/RMS/Work/FC/. If you wish to transfer an individual file, do the same but omit the option -r. If you wish to have another destination on the Sun where you wish to have the file(s) copied, type the path to this destination instead of the period. Ex.:

  	% scp ~/RCtool_Read_Me-2.3.pdf  w3_sysecol2@sysecol2.ethz.ch:htdocs/software/RCtool/pdfs/
  	

  Note, you may also be prompted for your own password on your own Mac and need to accept the key when asked. In case your user name on the Sun and the Mac differ, you need to specify the user name on your Mac as in the following example:

  	% scp afischli@semac01:/Volumes/HD2/Sim/RMS/Work/ForClim.SUP .
  	

  In case the two hosts are not on the same local area network, you may need also to give the full IP-name of your source machine. Ex.:

  	% scp afischli@semac01.ethz.ch:/Volumes/HD2/Sim/RMS/Work/ForClim.SUP .
  	

  see also OS X Hint and Example syntax for Secure Copy (scp)

  ---

• sftp
  sftp is the recommended alternative to ftp and you can use it whenever you have ssh access to a host. Ex.:

  	afischli$ sftp atitlan <- or whichever remote host you wanna connect to
  	Connecting to atitlan...
  	
  	|-----------------------------------------------------------------|
  	| This system is for the use of authorized users only.            |
  	...
  	snip
  	...
  	| evidence of such monitoring to law enforcement officials.       |
  	|-----------------------------------------------------------------|
  	
  	afischli@atitlan's password:   <- enter your password as requested 
  	sftp> pwd
  	Remote working directory: /home/afischli
  	sftp> cd /export/ftp/pub/docs/afischli/for-annett
  	sftp> lcd /Users/afischli/Desktop
  	sftp> put Fischlin-ForstKolloq.-Jan_08.pdf
  	Uploading Fischlin-ForstKolloq.-Jan_08.pdf to /export/ftp/pub/docs/afischli/for-annett/Fischlin-ForstKolloq.-Jan_08.pdf
  	Fischlin-ForstKolloq.-Jan_08.pdf             100%  113KB 113.0KB/s   00:00    
  	sftp> ls
  	Fischlin-ForstKolloq.-Jan_08.pdf        
  	sftp> quit
  	afischli$ 
  	...
  	

  Here you can use commands like cd, ls, put, and get, quit, and help etc. very similar to the ones you are used using with ftp. Above example transfers with the basic command put a pdf file to the host. The host serves as an anonymous ftp server and can thus offer large files to recipients. Note, large files (rule of thumb: >1MB) should not be attached to E-mails. Uploading them to a ftp server allows you to "send" such files nevertheless.

  OS X Hint: If you are using Apple's Terminal application you can drag and drop any object from the Finder to the the Terminal's window. Thus type e.g. put <blank> and then drag drop any file to the Terminal window. The result should be similar to this put /Users/afischli/Desktop/Fischlin-ForstKolloq.-Jan_08.pdf and only then press the <return> key. Remember, with Apple's Terminal there is little need to assemble complicated path names if you see your files or directories of interest already in the Finder.

  ---

• C
  

  On inawa and okee we have installed GNU C compilers. First basic help on okee type:

       /usr/local/bin/gcc --help    or    man gcc

  given MANPATH contains path /usr/local/man. On inawa gcc is too old to accept the --help option. However man gcc is fine.

  ---

• tar
  

  Archive entire branch of your filesystem, e.g. directory RASSDev into a new tar archive

       % tar cvf RASSDev.tar RASSDev

  Generates in file RASSDev.tar all files and subdirectories contained in directory RASSDev.

  Inspect a tar archive with

       % tar tvf RASSDev.tar | more

  Add some more files from your filesystem, e.g. a directory RASSDev/ISIS into an existing tar archive (RASSDev.tar)

       % tar rvf RASSDev.tar RASSDev/ISIS

  Extract a tar archive into its original branch of your filesystem

       % tar xvf RASSDev.tar

  Better is to restore also exactly all permissions with

       % tar xvfp RASSDev.tar

  (Note: Works fine if you own all files, otherwise you should be superuser to set all owners to the original values)

  Extract a single file from a tar archive:

       % tar xvf RASSDev.tar 
       e.g.: tar xvf RASSDev303.tar RASSDev303/a.RassTests.Diff

  On the Mac use suntar or Stuffit Deluxe to deal with tar archives (or use Terminal when you are working under OS X).

  Using tar with extended attributes may cause difficulties. To make a clean tar file without extended attributes of the directory "my_files", do the following:

       # copy my_files to the Desktop, excluding extended attributes
       cp -rX ~/Documents/my_files ~/Desktop/my_files
  
       # go to Desktop
       cd ~/Desktop
  
       # create the tar file, excluding .DS_Store files
       tar cjvf my_files.tar.bz2 -exclude .DS_Store my_files
  
       # remove the copy
       rm -r my_files

  ---

• mv branch
  

  Move an entire branch of your filesystem by means of tar. Example:
  

       % cd fromdir; tar cf - .| (cd todir; tar xfBp -)

  To move it to another server supporting rsh services:

       % cd fromdir; tar cf - .| rsh hostname cd todir\; tar xvBpf - 

  You will of course be prompted for username and password.

  ---

• Compression / Decompression
  Use gzip or compress. E.g. to compress file RASSDev.tar enter:

       % gzip RASSDev.tar 

  You should obtain the compressed file RASSDev.tar.gz in place of the original file. Uncompress such a file by

       % gunzip RASSDev.tar.gz

  Using compress respectively uncompress enter e.g.

       % compress RASSDev.tar 

  You should obtain the compressed file RASSDev.tar.Z. Uncompress such a file by

       % uncompress RASSDev.tar.Z 

  and you get back file RASSDev.tar

  ---

• ar (Archives)
  Look at a library archive:

       % ar -t /opt/epc/em2/lib/libSM2_p.a
              ...

  Extract a file:

       % ar -x /opt/epc/em2/lib/libSM2_p.a IEEECtrl1.def
              ...

  Replace a file:

       % ar -r /opt/epc/em2/lib/libSM2_p.a IEEECtrl1.def
              ...

  ---

• df (display file system statistics)
  call it to learn about the current disk space usage. Note, on our suns are several versions of this program around (e.g. /usr/bin/df, /usr/sbin/df, /usr/ucb/df, or /bin/df). The one most users seem to like best, i.e. the winner is: /usr/ucb/df. Set your paths or an alias (e.g. alias df /usr/ucb/df) accordingly.

  ---

• awk (filter rows by elements)
  Good tutorials: Awk by example, Part 1 Awk by example, Part 2

  ---

• tr (locale)
  Use tr to translate characters, typically in a pipe. Ex.:

       % cat myfile | tr '\015' '\012'

  converts the end of line characters used in Mac file myfile, i.e. ASCII CR (= octal 15), into the end of line characters of a Unix file, i.e. ASCII LF (= octal 12).

  However, often tr fails for reasons difficult to understand, in particular under Mac OS X. You may encounter this error

       tr: Illegal byte sequence

  Then use command locale to learn about your current language settings. Note that tr works only as designed if LCCTYPE=C. It is best then to override the global language settings of your computer for the use of tr temporarily. Either prefix your tr command with

       % cat myfile | LCCTYPE=C tr '\015' '\012'

  in the Bourne or bash shells or use following statement in the C shells:

       % setenv LC_CTYPE C ; cat myfile | tr '\015' '\012'

  and tr should again work as expected.

  ---

• apache (web server)
  

  On the host huron.ethz.ch we have installed the apache web server.

  As an ordinary user you may offer web pages in the folder public_html within your home directory. You may then access these "user-specific" web pages with the URL

  	     http://huron.ethz.ch/~username

  where username stands for your login name. Ex.:

  	     http://huron.ethz.ch/~forclim

  will access the web pages of the ForClim data base (access restricted).

  You can control the access to your web pages. For instance you may require a visitor to login and enter a password before the visitor may access your web pages. If your home directory contains a hidden file .htpasswd, then the access is restricted to those users listed in this file.

  To give some visitors access to your restriced web pages, you have to specify the visitor's name and a password.

  1. To specify the name by which the user can access your web pages, you have to define a so-called User ID or username for the visitor. Edit the file .htaccess and add the visitor's UserID similar to this example:

          AuthName "visiting this site as registered user"
          AuthUserFile /home/forclim/.htpasswd
          Require user myvisitor

     In this example the username is myvisitor. Note, this name is normally a different one than the name you use to login to the Unix host. It is only used to gain access to particular web pages, i.e. the web pages, which reside inside public_html within your own home directory. The visitor called myvisitor can visit the web pages contained in public_html only by the proper user name and the correct password (see below). Note, in this example it ist still the user forclim who owns all html files and has full control over the access to these files by visitors. There is no need to ask the system administrator for further support. Note also, this method to restrict access is not very safe. It is called "basic authentication" and provides only a simple access restriction with no security against sophisticated hackers (see also link to apache documentation below).
     
     

  2. To specify the password use the following command:

           /usr/apache/bin/htpasswd .htpasswd User ID

     The User ID is the same as listed in file .htacess (see previous step).

  With our installation of apache, you may execute your own cgi-bin, e.g. a perl script. Our installation requires that you store such a cgi-bin script within the directory cgi-bin inside the directory public_html.

  More on apache can be found here.

  ---

• vi (editor)
  

  Excellent help information is available here:

  • vi Cheat Sheet
  • Advanced vi Cheat Sheet
  • vi Hint Sheet

• You can mount our Unix machines from any Apple Macintosh machine. Use the Chooser and select AppleShare service. Then select the host in the list of the displayed hosts (our Unix machines should show up in the AppleTalk zone "ito.umnw.machines_sgb"). Alternatively it is possible to select the host by clicking onto the button "Server IP Address" and then enter the host's name, e.g. inawa.ethz.ch (or even simpler inawa). The latter method is the only one to connect from outside ETHZ via TCP/IP. The latter method works also via PPP and modem.

  Instructions of how to use the software, which provides this service (it's called netatalk) can be found on e.g. inawa. Use Unix command man e.g.

  	
  	    man afpd     - AppleTalk Filing Protocol daemon
              man atalkd   - System administration only
              man papd     - System administration only
              man psf      - Printing postscript files via Unix
          

• Ever scratched your head and wondered what that damned Unix command might be called you need right now to accomplish a certain task? If that's true, the following hints are for you. Otherwise, skip it, you simply don't need it, since you are a UNIX GURU of the 10th Dan. ;-)
  • Unix Quick Reference Guide offers useful summaries for the most common commands
  • One-Liners a useful bunch of Unix commands
  • man command
    Use it to learn how to use a certain command
    Also man [section number] command

    man(ual) pages & more (OS X specific, spin-off from the Huntsville Macintosh Users Group)

    Unix manual pages

    useful while on a non-Unix system but having at least access to the internet

    Click here... for other links useful in this context

   

• Recommended reading:
  
  Abrahams, P.W. & Larson, B.R., 1992. UNIX for the impatient. Addison-Wesley, Reading a.o., 559pp. Ab02SE

   

  Misc hints:

  talk user

  Use it to talk to another user, who is currently also online

  df

  Learn about free disk space, which is currently available

  /usr/sbin/nslookup url

  Learn about the IP# of the url (uniform resource locator)

  uname -a and hostid

  Learn about a machines OS, IP