Development of basic Bash text utilities: cat, grep, for working with C programming language texts. These utilities (cat and grep) are often used in the Linux terminal for work with text and files.
cat is a standard Unix utility that reads files sequentially, writing them to standard output. The name is derived from its function to concatenate files. It has been ported to a number of operating systems.
cat was part of the early versions of Unix, e.g., Version 1, and replaced pr, a PDP-7 and Multics utility for copying a single file to the screen.
It was written by Ken Thompson and Dennis Ritchie. The version of cat bundled in GNU coreutils was written by Torbjorn Granlund and Richard Stallman.The ReactOS version was written by David Welch, Semyon Novikov, and Hermès Bélusca.
Cat is one of the most frequently used commands on Unix-like operating systems. It has three related functions with regard to text files: displaying them, combining copies of them and creating new ones.
cat [OPTION] [FILE]...
| No. | Options | Description |
|---|---|---|
| 1 | -b (GNU: --number-nonblank) | numbers only non-empty lines |
| 2 | -e implies -v (GNU only: -E the same, but without implying -v) | but also display end-of-line characters as $ |
| 3 | -n (GNU: --number) | number all output lines |
| 4 | -s (GNU: --squeeze-blank) | squeeze multiple adjacent blank lines |
| 5 | -t implies -v (GNU: -T the same, but without implying -v) | but also display tabs as ^I |
Thompson wrote the first version in PDP-11 assembly language to help Lee E. McMahon analyze the text of the Federalist Papers to determine authorship of the individual papers. The ed text editor (also authored by Thompson) had regular expression support but could not be used on such a large amount of text, so Thompson excerpted that code into a standalone tool. He chose the name because in ed, the command g/re/p would print all lines matching a specified pattern. grep was first included in Version 4 Unix. Stating that it is "generally cited as the prototypical software tool", McIlroy credited grep with "irrevocably ingraining" Thompson's tools philosophy in Unix.
grep [options] template [file_name]
| No. | Options | Description |
|---|---|---|
| 1 | -e | pattern |
| 2 | -i | Ignore uppercase vs. lowercase. |
| 3 | -v | Invert match. |
| 4 | -c | Output count of matching lines only. |
| 5 | -l | Output matching files only. |
| 6 | -n | Precede each matching line with a line number. |
| 7 | -h | Output matching lines without preceding them by file names. |
| 8 | -s | Suppress error messages about nonexistent or unreadable files. |
| 9 | -f file | Take regexes from a file. |
| 10 | -o | Output the matched parts of a matching line. |
- The program developed in C language of C11 standard using gcc compiler
- Did not use outdated and legacy language constructions and library functions. Used the POSIX.1-2017 standard.
- Integration tests covered all flag variants and input values, based on a comparison with the behavior of real Bash utilities
- The programs are executable files with command line arguments
- Full coverage of library functions code with unit-tests using the Check library
- Use a Makefile for building the library and tests (with targets all, clean, test, v1_cat, v1_grep)
- The program has only been tested on a MacOS.