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optics.csufresno.edu Class Files - ECE 70 HOWTOs
Department of Electrical and Computer Engineering
Dr. Gregory R. Kriehn, Professor

HOWTO Use Various Commands in Unix/Linux

1. Listing Files

To list the contents of a directory, use ls:

        ~> ls
        a.out*       distance.o   hw2.c        hw5.c*             
        ascii.c      examples/    hw2.o*       mail/      
        ascii.o*     hw1.c        hw3.c        multiple.c
        distance.c   hw1.o*       hw4.c        multiple.o*
        ~>

Note:  The * indicates an executable file.
       The / indicates a directory.


2. Copying Files

To copy a file from one place to another:

        cp [source-file] [target-file]

        ~> cp hw1.c hw3.c
        ~>

You now made a copy of hw1.c, which is called hw3.c.


3. Moving Files

To move a file:

        mv [source-file] [target-file]

        ~> mv hw1.c hw4.c
        ~>

Now, hw1.c no longer exists. It is now called hw4.c. Be careful!


4. Deleting Files

To delete a file:

        rm [filename]

        ~> rm hw1.bad
        rm: remove hw1.bad (yes/no)? yes
        ~>

Now, hw1.bad no longer exists.  Be VERY careful!!!


5. Manual (man) Pages

To learn about other commands, use the man(ual) pages:

 ~> man nano

will tell you more than you ever wanted to know about nano...

To exit the man page, typ
e 'q'.


6. Examining Files

Using "more" or "less" allows you to look at files:

  ~> more distance.c
 /* ------------------------------------------------------------ */
 /* Program Example -- Distance                                  */
 /*                                                              */
 /* This program computes the distance between two points.       */
 /* ------------------------------------------------------------ */
                                                                               
 #include <stdio.h>
 #include <math.h>
                                                                               
 int main(void)
 {
         /* Declare and initialize variables */
         double x1 = 1, y1 = 5, x2 = 4, y2 = 7;
         double side_1, side_2, distance;
 
         /* Compute the sides of the triangle */
         side_1 = x2 - x1;
         side_2 = y2 - y1;
 
         distance = sqrt(side_1*side_1 + side_2*side_2);
 
         /* Print the distance */
 --More--(77%)

(Hit space bar to continue)

"more" will only allow you to look forwards in a file (not backwards)--use the space bar to do so.  Using "less", you can look both backward and forward by using the "Page Up" and "Page Down" keys, as well as the "Up Arrow" and "Down Arrow" keys to move backward or forward one line at a time.  Type 'q' to exit when using "less".


7. Piping the Output of One Command into the Input of Another Command

You can pipe the output of one command to another using "|"

  ~> deg_to_rad.o | more
  Degrees to Radians
       0  0.000000
      10  0.174533
      20  0.349066
      30  0.523599
      40  0.698132
      50  0.872665
      60  1.047098
      70  1.221731
      80  1.396264
      90  1.570796
     100  1.745329
     110  1.919862
     120  2.094395
     130  2.268928
     140  2.443461
     150  2.617994
     160  2.792527
     170  2.967060
     180  3.141593
     190  3.316126
     200  3.490659
  --More--