Files and Directory
cd /home	enter to directory '/ home'
cd ..	go back one level
cd ../..	go back two levels
cd	go to home directory
cd ~user1	go to home directory
cd -	go to previous directory
pwd	show the path of work directory
ls	view files of directory
ls -F	view files of directory
ls -l	show details of files and directory
ls -a	show hidden files
ls *[0-9]*	show files and directory containing numbers
tree	show files and directories in a tree starting from root(1)
lstree	show files and directories in a tree starting from root(2)
mkdir dir1	create a directory called 'dir1'
mkdir dir1 dir2	create two directories simultaneously
mkdir -p /tmp/dir1/dir2	create a directory tree
rm -f file1	delete file called 'file1'
rmdir dir1	delete directory called 'dir1'
rm -rf dir1	remove a directory called 'dir1' and contents recursively
rm -rf dir1 dir2	remove two directories and their contents recursively
mv dir1 new_dir	rename / move a file or directory
cp file1 file2	copying a file
cp dir/* .	copy all files of a directory within the current work directory
cp -a /tmp/dir1 .	copy a directory within the current work directory
cp -a dir1 dir2	copy a directory
ln -s file1 lnk1	create a symbolic link to file or directory
ln file1 lnk1	create a physical link to file or directory
touch -t 0712250000 file1	modify timestamp of a file or directory - (YYMMDDhhmm)
file file1	outputs the mime type of the file as text
iconv -l	lists known encodings
iconv -f fromEncoding -t toEncoding inputFile > outputFile	creates a new from the given input file by assuming it is encoded in fromEncoding and converting it to toEncoding.
find . -maxdepth 1 -name \*.jpg -print -exec convert "{}" -resize 80x60 "thumbs/{}" \;	batch resize files in the current directory and send them to a thumbnails directory (requires convert from Imagemagick)