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Information about the NIS System and UNIX Primer

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Logon Information

  • Use your userid and the password to logon to any of our cluster computers.
  • Remote login from one system to the other is also possible using ssh command. For example, if you wish to logon to thebe, just type ssh thebe and press enter in your terminal.
  • If you are not in our network and still want to connect to our computers, then you should first ssh to and then ssh to other computers.

    Computers Available

    Computer Name Type/OS Processor Memory Disk Drive(s) Physical Location Serial Number Linux/Kubuntu11.10 Intel Core quad Q6000 4.0 GiB /atiic1 
    AH 5.210 08:00:69:05:fb:85 Linux/Kubuntu11.10 Intel Xeon 3.06 GHz 1.0 GiB /metis1
    AH 5.210 08:00:69:0e:91:b7
 Linux/Kubuntu11.10 /lysithea1
    AH 5.210 08:00:69:0e:67:e8 Linux/Kubuntu11.10 AMD Phenom X6 16 GiB /adrastea1
    AH 5.210 08:00:69:0e:67:dc Linux/Kubuntu11.10 Intel Pentium 4 512 MB AH 5.408 08:00:69:05:ab:15 Linux/Redhat Intel Pentium 4 512 MB /u
    AH 5.210 08:00:69:05:ab:15 Linux/Redhat Intel Pentium D 2.0 GiB /adrastea3
    AH 5.412 08:00:69:05:ab:15

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    UNIX Primer

    man command_name
                            probably one of the most useful UNIX commands. 
                            man shows a help file on a certain command, including all options
                            and examples.
                            example:  man ls

    pwd to show current location on directory tree (stands for "print working directory") Example, after logging into the NIS system you will be in your home directory; Issuing the command "pwd" will return something like /u/people/joe_user

    ls -l to list files, subdirectories and symbolic links in a directory (the option gives "long format" which includes additional information about the files, such as sizes, last modification date, ownership, etc) Example: to look at the files in your home directory, issue the command "ls -l"

    lrwxr-xr-x 1 ahinck user 18 Jul 1 2000 bin -> /inept2/ahinck/bin drwxr-xr-x 2 ahinck user 4096 Sep 12 1999 dumpster -rw-r--r-- 1 ahinck user 53606 Jan 4 22:59 protein.jpeg

    above, the first letter of the permissions (-rw-r--r--) shows the type of the file. l is a symbolic link, d is a directory, and - is a regular file. See description of chmod below for more information about permissions.

    cd dir_spec to change to the directory specified by dir_spec (e.g. cd /inept2/joe_user)

    cp file1 file2 to copy file1 to a new name: cp <file1> <file2>

    cal withough argument, prints the calendar for the current month Otherwise, prints a 12-month calendar for the specified year or month example: cal 7 2003 -- prints the calendar for July of 2003

    who displays the names of the users currently logged onto the system whoami prints the username of the invoking user

    ps -ef produce a full listing of all active processes on a given machine often used in conjunction with the command grep: ps -ef | grep joe_user lists all active processes for a given joe_user

    grep exp file search one or more files for a given expression example: grep moo my_output.txt

    mkdir name create a new directory name mkdir my_stuff -- creates a new directory my_stuff

    rm files remove one or more files rm file.txt -- deletes the file file.txt

    rm -r file if removing a directory, remove it and all its contents, including subdirectories

    ls -lR make a recursive long format list of all subdirectories as well as current directories. It is very useful for finding the name of the file you might not quite remember. example: ls -lR | grep string -- lists all the files in the current directory and its subdirectories that contain the string in their filename

    find /dir -name filename.x -print search for a file with the name filename.x in the given directory and, if found, print the path of the file find /work -name blah -print -- lists all the files named "blah" in the /work directory

    bc -l calls a basic calculator that performs arithmetics

    cat files read one or more files and print then on standard output you can use the > operator to combine several files into one or the >> operator to append files to an existing one cat ch1 ch2 ch3 > all -- combines three files into "all" cat note5 >> notes -- add note5 to notes

    date print the current date and time

    du -s directory print disk usage recursively in number of 512-byte blocks for each named directory

    chmod permissions (-rw-r--r--) specify who has who has access to a given file. The first three letters are for user, the owner of the file, second tripletis for group, and the last is for others. r is read permission, w is write permission,and x is execute permission. Thus, in the example above, the owner of the file can readand write to it, the group and only read, and all others can only read it.chmod command changes the access mode of one or more files. the access mode is madefrom concatenating the following:

    u -- user + -- add permission g -- group - -- remove permission o -- other = -- assign permission a -- all (default) r -- read w -- write x -- execute

    chmod u=rwx, g=rx, o=x file -- sets read-write-execute permission by owner, read-execute by group, and execute-only by others the given file

    chown newowner files change the ownership of one or more files to newowner newowner is a username

    vi filename open or create a file in vi editor. vi editor tutorial

    kill -9 IDs kill one or more processes with specified IDs. These IDs can be aquired by listing the processes with the ps -ef command.

    lp -d laser1 filename print a file to destination laser1, Hincklab HP4000

    ln -s file1 file2 create a symbolic link from file1 to file2. file2 can also be a directory. this command creates a link across the system so that you don't need to copy the directory or file.

    mv source target move the souce file to a target file, i.e. delete the source and copy it as target. This command is useful for renaming files. mv cow.txt /farm/cow2.txt -- moves the file cow.txt to the directory /farm and names it cow2.txt

    more file displays the named file on the terminal, one screenful at a time. Press spacebar for the next screnful.

    passwd create or change a password associated with a username. only the actual user or the priveleged user can do this.

    sort -op files sort the lines of the files, usually in alphabetical order. -b ignore leading spaces -d sort in dictionary order -f ignore upper/lowercase differences -n sort numerically

    su -username create a shell with a username of another user. If no username is specified, become a super user. Enter EOF to terminate

    tar copy files or restore files from tape. See the tape device help page for commands

    wc -l filename count the lines in a given file.

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    Programming Languages Supported

    C Programming (cc)
    Numerical Recipes in C - Provides useful mathmetical C programming routines, see help page

    FORTRAN (f77)



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    Last updated on February 02, 2012