unix.txt

cp
==
cp file1 file2          creates file2 in the current directory that is a copy of file1.
cp file dir             copies file into directory dir.
cp -R* dir              copy recursively all into directory dir
cp -R dir1 dir2	        copy recursively from  dir1 to dir2

mv
==
mv old new              renames old to new
mv -i old new           to be prompted before overwriting, overwrite (y/n)?

mv old new              renames old to new moves file into dir

find 
====
find all files with .html extension in the current dir
find *.html

move all files in the current directory js (*js) to destination /var/www/js
find *js -exec mv {} /var/www/html/js \;

find all the file names that end with the .html file extension in the current dir denoted by (.)
find . -name \*.html -print

list all files whose names do not end in c
find / \! -name "*.c" -print

change directory permissions to 777 recursively  
find /dir/here -type d -exec chmod 777 {} \;

change files permissions to 777 recursively 
find /dir/here -type f -exec chmod 777 {} \;

grep
====
find "text" in dir/path recursively(r) and line-number(n)
grep -rn "text" dir/path

redirect output to file.txt
grep -r "text" dir/path > file.txt 2>&1

list files that start with 'a'
ls | grep '^a'

list files that end with '.gif'
ls | grep '.gif$'

list files alphabetically 
ls | sort

list files alphabetically in reverse
ls | sort -r