Use the shell test to validate basic file information.
10354
Why *not* parse `ls` (and what to do instead)?
95242
How to read from input file (text file) and validate input as valid integer?
153428
Bash script: check if a file is a text file
63822
Verify if file exists or not in C#
48172
Test if file is locked
86719
How to check if file is empty or it has only blank characters?
133811
How can I create a shelltoast?
120034
Simulate file structure with PHP
30954
How do you validate a binary search tree?
92335
Check if a file is executable
152983
How can I test for POSIX compliance of shell scripts?
141259
shell scripting if statement doesn't work
14252
How to represent multiple conditions in a shell if statement?
52761
Running shell command and capturing the output
22156
How do I tell if a regular file does not exist in Bash?
82583
Checking for interactive shell in a Python script
123823
File input 'accept' attribute - is it useful?