find all files with extension linux code example

Example 1: how can I find perticular extension in ubuntu?

find . -type f -name "*.txt"

Example 2: terminal find file by extension recursive

find /directory/path -type f -name "*.in"

Example 3: find linux with extension

find /home/username/ -name "*.err"

Example 4: bash find files with extension

# syntax
find </path/to/dir> -name '.<extension>'

# example 
find /export/home/jacquesk -name '*.txt'

# This will search in folder-path (including subdirectories) 
# of "/export/home/jacquesk", and will show any files 
# that end in '.txt'

Example 5: linux give all files an extension

for file in * ; do  mv "$file" "$file.md"; done

Example 6: linux find file

# syntax 
# find *</path/to/dir> '(' *<Filter-1> *<and/or-operator> *<filter-2> ')'

# example 
find . '(' -name "Test*.pm" -a ! -name 'Useless*' ')'