Linux Finding Files

Finding Files in Linux

There are several ways to find files in Linux when you don’t know their exact location. This guide covers the most common tools and adds useful tips and examples.

1. `find`

If you have a rough idea of the directory tree where the file might be, you can use find:

find directory -name targetfile -print

For example:

find /home -name "*.txt" -print 2>/dev/null

*.txt → matches all text files
2>/dev/null → suppresses permission error messages
Quotes (") → prevent the shell from expanding the *

Useful Options

By type:
find . -type f → only files
find . -type d → only directories
By permissions:
find . -perm o=r → files readable by others
By size:
find . -size +10M → files larger than 10 MB
Execute commands on matches:
Terminal window
```
find . -name "*.txt" -exec wc -l '{}' ';'
```
Counts the lines in every .txt file.
Case-insensitive search:
Terminal window
```
find . -iname "*.jpg"
```

📌 For more details: man find or info find

2. `which` (sometimes `whence`)

If you can run a command, you can locate its binary on disk:

> which ls
/bin/ls

Useful Alternatives

type ls → shows if it’s a built-in, alias, or binary
command -v ls → POSIX-compliant alternative to which

3. `locate`

locate uses a prebuilt index of filenames, making it much faster than find.

Example:

locate ".txt"

This will list all files with .txt in their path.

Notes

The index is usually updated daily. To refresh it manually:
Terminal window
```
sudo updatedb
```
May list files that have been deleted or miss very new files.
Unlike find, it cannot filter by permissions, size, or type.

Comparison

Command	Speed	Freshness of results	Search criteria	Example use case
find	Slow	Always up-to-date	Flexible (name, size, type, perms, exec)	General-purpose searching
which	Fast	Always up-to-date	Executables only	Find binary locations
locate	Very fast	May be outdated	Filename patterns only	Quickly list many matches

Other Useful Tools

whereis <command> → shows binary, source, and man page location
fd <pattern> → a modern, faster alternative to find (if installed)
grep -rl <pattern> <dir> → find files containing a text string