Development of Bash text utilities: cat, grep.
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 |
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. |