Directory Content:

scanzio@fly:~/0-cloud/2-corsi/4-os/es/u03s03e$ ls -la
total 48
drwxr-xr-x  2 scanzio scanzio 4096 set  3 15:37 .
drwxr-xr-x 19 scanzio scanzio 4096 set  3 15:09 ..
-rw-r--r--  1 scanzio scanzio   62 set  3 15:36 aAa.txt
-rw-r--r--  1 scanzio scanzio   62 set  3 15:09 aAa.x
-rw-r--r--  1 scanzio scanzio   62 set  3 15:09 aa.x
-rw-r--r--  1 scanzio scanzio   62 set  3 15:09 aBcBa.txt
-rw-r--r--  1 scanzio scanzio   62 set  3 15:09 aBcBa.x
-rw-r--r--  1 scanzio scanzio   70 set  3 15:09 a.txt
-rw-r--r--  1 scanzio scanzio   62 set  3 15:09 a.x
-rw-r--r--  1 scanzio scanzio  101 set  3 15:09 b.txt
-rw-r--r--  1 scanzio scanzio   87 set  3 15:09 c.txt
-rw-r--r--  1 scanzio scanzio 2194 set  3 15:09 find.txt

P.S. The find command prints the file names as ./name.ext (i.e., with the path ./)

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Name:

find . -name 'a.*'
find . -name 'a.*' -print
find . -name 'A.*' -print --> NOTHING
find . -iname 'A.*' -print  --> same files as with a.*
find . -name 'a*a.*' -print

Regular expressions:

find . -name '*' -print --> ALL
find . -regex '*' -print --> NOTHING must be replaced with
find . -regex '.*' -print

find . -regex '\./...' -print --> ./a.x because \. == ., then /, and 3 characters

find . -regex '..\(.\).\1.*' -print --> palindrome strings of 3 characters,
                                        but preceded by 2 characters .. (./) and followed by
                                        everything .*


find . -regex '..\(.\)\(.\).\2\1.*' -print --> palindrome strings of 3 characters

find . -rexex ".*a{2}.*" --> DON'T work
find . -rexex ".*a\{2\}.*" --> DON'T work
find . -rexex ".*aa.*" --> OK

find . -size +500c --> All the file of dimension >= 500 bytes
find . -size -500c --> All the file of dimension < 500 bytes

find . -type f --> All the regular files
find . -type l --> Al the symbolic links

find . -user scanzio
find . -readable
find . -executable

find . -mindepth 3 -maxdepth 5 -name "*.c"
   --> before min/maxdepth, then -name

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Prints the first match and quit (it does not print without -print)
find . -name "*.x" -print -quit

Prints the first 2 lines of all the files
find . -name "*.txt" -exec head -n 2 '{}' ';'
the same
find . -name "*.txt" -exec head -n 2 \{} \;

Concatenates all the files with extension .txt in the file a (USE OF REDIRECTION)
find . -name "*.txt" -exec cat '{}' >> a ';'

Creates the directory ./dir and copy all the files with extension .txt in the directory ./dir
find . -name "*.txt" -exec cp -f '{}' ./dir ';'

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