# find, search, grep

## find


### use cases:

* `find ./subfolder -name sample.txt` - Search a file with specific name
* `find ./subfolder -name *.txt` - Search a file with pattern
* `find ./GFG -name sample.txt -exec rm -i {} \;` - find and delete a file with confirmation
* `find ./subfolder -empty` - Search for empty files and directories
* `find ./subfolder -perm 664` - Search for file with entered permissions
* `find ./ -type f -name "*.txt" -exec grep 'some Phrase'  {} \;` - Search text within multiple files
  
#### more examples

```bash
find /path -name *.txt
find /path -type f -name test.txt
find /path -name failed*.* -type f
find /path -type f -not -name "*.html"
find / -name "file.txt" -size +4M
find /dev/ -type b -name "sda*"
find ./*file*
```


## grep

`grep [OPTION]... PATTERNS [FILE]...`

* options
  * `-B <numb>` - show numb lines before match
  * `-A <numb>` - show numb lines after match
  * `-i` - ignore case distinctions in patterns and data
  * `-r`, `--recursive` - like --directories=recurse
  * `-v`, `--invert-match` - To display only the lines that do not match a search pattern
  * `--exclude-dir=<foldername>` - exclude folder from search
  * `-n`, `--line-number` - Prefix each line of output with the 1-based line number within its input file.

### examples

* `grep -ir --exclude-dir=vendor skeleton .` - find all occurences of "skeleton" in the current working dir
* `grep -i "some string" path/**/files.log` - search string in log files


## sed

`sed -i 's/SEARCH_REGEX/REPLACEMENT/g' INPUTFILE`

* `-i` - By default, sed writes its output to the standard output. This option tells sed to edit files in place. If an extension is supplied (ex -i.bak), a backup of the original file is created.
* `s` - The substitute command, probably the most used command in sed.
* `/ / /`` - Delimiter character. It can be any character but usually the slash (/) character is used.
* `SEARCH_REGEX` - Normal string or a regular expression to search for.
* `REPLACEMENT` - The replacement string.
* `g` - Global replacement flag. By default, sed reads the file line by line and changes only the first occurrence of the SEARCH_REGEX on a line. When the replacement flag is provided, all occurrences are replaced.
* `INPUTFILE` - The name of the file on which you want to run the command.