changed file names and directories

landing/docs/commands/files/cat.md

@@ -0,0 +1,153 @@
+# The `cat` command
+---
+
+The `cat` command allows us to create single or multiple files, to view the content of a file or to concatenate files and redirect the output to the terminal or files.
+
+The "cat" stands for 'concatenate.' and it's one of the most frequently used commands in the Linux terminal.
+
+
+### Examples of uses:
+
+
+1. To display the content of a file in terminal:
+
+```
+cat <specified_file_name>
+```
+
+2. To display the content of multiple files in terminal:
+
+```
+cat file1 file2 ...
+```
+
+3. To create a file with the cat command:
+
+```
+cat > file_name
+```
+
+4. To display all files in current directory with the same filetype:
+
+```
+cat *.<filetype>
+```
+
+5. To display the content of all the files in current directory:
+
+```
+cat *
+```
+
+6. To put the output of a given file into another file:
+
+```
+cat old_file_name > new_file_name
+```
+7. Use cat command with `more` and `less` options:
+
+```
+cat filename | more
+cat filename | less
+```
+
+8. Append the contents of file1 to file2:
+
+```
+cat file1 >> file2
+```
+
+9. To concatenate two files together in a new file:
+
+```
+cat file1_name file2_name merge_file_name
+```
+
+10. Some implementations of cat, with option -n, it's possible to show line numbers:
+
+```
+cat -n file1_name file2_name > new_numbered_file_name
+```
+
+
+### Syntax:
+
+```
+cat [OPTION] [FILE]...
+```
+
+### Additional Flags and their Functionalities:
+
+|**Short Flag**   |**Long Flag**   |**Description**   |
+|:---|:---|:---|
+|`-A`| `--show-all` |equivalent to -vET|
+|`-b`| `--number-nonblank` |number nonempty output lines, overrides -n|
+|`-e`|<center>-</center>| equivalent to -vE|
+|`-T`|<center>-</center>|Display tab separated lines in file opened with ```cat``` command.|
+|`-E`|<center>-</center>|To show $ at the end of each file.|
+|`-E`|<center>-</center>|Display file with line numbers.|
+|`-n`| `--number`|number all output lines|
+|`-s`| `--squeeze-blank`|suppress repeated empty output lines|
+|`-u`|<center>-</center>|(ignored)|
+|`-v`| `--show-nonprinting`|use ^ and M- notation, except for LFD and TAB|
+|<center>-</center>|`--help` |display this help and exit|
+|<center>-</center>|`--version`|output version information and exit|
+
+
+---
+
+
+# The `tac` command
+
+`tac` is a Linux command that allows you to view files line-by-line, beginning from the last line. (tac doesn't reverse the contents of each individual line, only the order in which the lines are presented.) It is named by analogy with `cat`.
+
+
+### Examples of uses:
+
+
+1. To display the content of a file in terminal:
+
+```
+tac <specified_file_name>
+```
+
+2. This option attaches the separator before instead of after.
+
+```
+tac -b concat_file_name tac_example_file_name
+```
+3. This option will interpret the separator as a regular expression.
+```
+tac -r concat_file_name tac_example_file_name
+```
+4. This option uses STRING as the separator instead of newline.
+```
+tac -s concat_file_name tac_example_file_name
+```
+
+5. This option will display the help text and exit.
+
+```
+tac --help
+```
+6. This option will give the version information and exit.
+
+```
+tac --version
+```
+
+### Syntax:
+
+```
+tac [OPTION]... [FILE]...
+```
+
+### Additional Flags and their Functionalities:
+
+|**Short Flag**   |**Long Flag**   |**Description**   |
+|:---|:---|:---|
+|`-b`|`--before`|attach the separator before instead of after|
+|`-r`| `--regex`|interpret the separator as a regular expression|
+|`-s`| `--separator=STRING`|use STRING as the separator instead of newline|
+|<center>-</center>|`--help`|display this help and exit|
+|<center>-</center>|`--version`|output version information and exit|