You can search for a text string in a currently opened file in the editor. Using different options, you can narrow your search process, use regular expressions in your search, and manage your search results.
Find the search string in a file
Open your file in the editor.
From the main menu, select Edit | Find | Find (Ctrl+F).
In the search field that opens, enter your search string. CLion highlights the results of your search in the file.
Replace the search string in a file
Press Ctrl+R to open the Replace in File window.
In the top field, enter your search string. In the bottom field, enter your replacement string. Click for a multi-line replace. For example, if you want to replace a comma with a comma and a new line, enter a comma in the search field and a comma and the new line in the replace field.
Click Replace to replace items one by one, Replace all to replace all items in your file, and Exclude to omit some items from replacing.
The options that appear in the Replace window, are similar to the Find window and you can refer to the manage the search results section.
Manage your search
CLion lets you adjust your search process and perform various actions with the displayed search results.
If you want to see the list of previous searches, press Alt+Down in the search field.
If you want to enter a multi-line string, click the icon in the search field for a new line.
Use the and arrows to navigate to the previous or the next occurrence.
Work with the list of occurrences (Alt+F7) in the Find tool window, where you have other options, for example, to group your results or to open them in a separate window.
Click the or icon to add a selection of the next occurrence or deselect the previous occurrence (Alt+J or Shift+Alt+J).
If you want to quickly replace the target of your search in the whole file, press Ctrl+Shift+Alt+J and type a new string.
You can narrow your search when you select the Words, Match case checkboxes on the search pane, or click the filter icon to select a scope for your search.
You can press Alt+X (previously known as Alt+G) to quickly select or clear the Regex checkbox. You can use regular expressions to opt for more challenging searches.
Press Ctrl+F7 to see usages of any element in the opened file.
If you don't want CLion to highlight all found usages in the file, open the Settings / Preferences dialog (Ctrl+Alt+S) and on the Editor | General page clear the Highlight usages of element at caret option.
Press Alt+F7 to search for usages beyond the current file or Ctrl+Alt+F7 to open the search results in a separate popup. If you need to configure some options before the search, press Ctrl+Shift+Alt+F7 to open the Find Usages dialog.
for a multi-line replace. For example, if you want to replace a comma with a comma and a new line, enter a comma in the search field and a comma and the new line in the replace field. 
and 
arrows to navigate to the previous or the next occurrence. 
or 
icon to add a selection of the next occurrence or deselect the previous occurrence (Alt+J or Shift+Alt+J). 
icon to select a scope for your search.