Add echo, egrep and fgrep content

* added echo content

* added egrep content

* added fgrep content

* Update 133-fgrep.md

* Update content/roadmaps/102-devops/content/102-managing-servers/101-live-in-terminal/127-echo.md

* Update content/roadmaps/102-devops/content/102-managing-servers/101-live-in-terminal/133-fgrep.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/102-devops/content/102-managing-servers/101-live-in-terminal/127-echo.md

@@ -1 +1,8 @@
-# Echo
+# echo
+
+`echo` is a built-in command in Linux used to display lines of text/string that are passed as an argument. It is mostly used in shell scripts and batch files to output status text or `ENV` variables to the screen or a file. 
+
+It has the following syntax: `$ echo [options] [string]` e.g. `$ echo "Hello World!"`
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.tecmint.com/echo-command-in-linux/'>Echo command with Examples</BadgeLink>

content/roadmaps/102-devops/content/102-managing-servers/101-live-in-terminal/132-egrep.md

@@ -1 +1,12 @@
-# Egrep
+# egrep
+
+`egrep` (**E**xtended **Grep**) is a pattern searching command which belongs to the family of grep functions. It treats the pattern as an extended **regular expression** and prints out the lines that match the pattern.
+It works the same way as `$ grep -E` command
+
+It has the following syntax:
+
+`$  egrep [options] pattern [files]` e.g. `$ egrep "search-regex" *.txt`
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://linuxhint.com/linux_egrep_command_examples/'>Egrep command with examples</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.thegeekdiary.com/fgrep-command-examples-in-linux'>options</BadgeLink>

content/roadmaps/102-devops/content/102-managing-servers/101-live-in-terminal/133-fgrep.md

@@ -1 +1,13 @@
-# Fgrep
+# fgrep
+
+`fgrep` (**F**ixed **Grep**) command is used for searching fixed-character strings in a file.
+It treats meta-characters or regular expressions in the search field as strings. For searching any **direct string** or files having meta-characters, this is the version of grep which should be selected. It works the same way as `$ grep -F` command.
+
+It has the following syntax:
+
+`$  fgrep [options] [string] [files]` e.g. `$ fgrep "search-string" file.txt`
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.geeksforgeeks.org/fgrep-command-in-linux-with-examples/'>Fgrep command with examples</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.thegeekdiary.com/fgrep-command-examples-in-linux/'>options</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.tecmint.com/difference-between-grep-egrep-and-fgrep-in-linux/'>Grep vs Egrep vs Fgrep</BadgeLink>