Week 4

Introduction

Over the past week, laboratory work 11 and 12 was completed on the following topics:

1. Programming in the command processor OS UNIX. Branches and cycles.
2. Programming in the command processor OS UNIX. Advanced programming.

Lab #11

As a result of the laboratory work, I learned the basics of programming in the UNIX OS shell. I learned how to write more complex batch files using logical control structures and loops..

Tasks were completed on the following topics:

1. Using the getopts grep commands, write a batch file that parses command line with switches: – -iinputfile — read data from the specified file; – -ooutputfile — output data to the specified file; – -ppattern — specify a search pattern; – -C — to distinguish between large and small letters; -n Print line numbers. and then searches the specified file for the necessary lines, determined by the -p switch.
2. Write a C program that takes in a number and determines if it is greater than zero, less than zero, or equal to zero. The program is then terminated with exit(n) function, passing the exit code information to the shell. Team- ny file should call this program and, after parsing with the command $?, display a message telling you what number was entered.
3. Write a batch file that creates the specified number of files, numbered sequentially from 1 to 𝑁 (for example, 1.tmp, 2.tmp, 3.tmp, 4.tmp, etc.). Number of files to be created is passed as command line arguments. This same co- The mand file must be able to delete all files created by it (if they exist).
4. Write a batch file that, using the tar command, packs into an archive all files in the specified directory. Modify it so that it packs only files that have been modified less than a week ago (use find command)

Lab #12

Studied the basics of programming in the UNIX OS shell. learned to write more complex batch files using logical control constructs and cycles.

The following tasks were solved:

1. Write a batch file that implements a simplified semaphore mechanism. Co- mand file must wait for some time t1 to be released resource, issuing a message about it, and after waiting for its release, use it for some time t2<>t1, also giving out information that the resource is used by the corresponding batch file (process). Run batch file in one virtual terminal in the background by redirecting its output to another (> /dev/tty#, where # is the terminal number where the output) in which this file is also running, but not in the background, but in a privileged mode. Refine the program so that there is the possibility of interaction between the three or more processes.
2. Implement the man command using a batch file. Explore the contents of the log /usr/share/man/man1. It contains archives of text files containing help on most of the programs and commands installed in the system. Each archive can be opened with the less command by immediately viewing the contents of the help. Command the file must receive the name of the command as a command line argument and in the form output a help about this command or a message about the lack of help, if the corresponding file is not in the man1 directory.
3. Using the $RANDOM built-in variable, write a batch file that generates generating a random sequence of letters of the Latin alphabet. Note that $RANDOM produces pseudo-random numbers in the range from 0 to 32767

Conclusions

Over the past week, I’ve learned the basics of UNIX shell programming. I also learned how to write more complex batch files using logical control structures. and cycles. The tasks were interesting, but difficult, so I solved them for quite a long time and not without someone else’s help. In general, I am satisfied with the results of the past week, I completed all the work in advance and I did not have any particular difficulties.