mondwan

# Extract files fomr mydir.tar
tar xvf mydir.tar

# Create the archive for file mydir and compress with gzip 
tar zcvf mydir.tar.gz mydir

# Create the archive for file mydir and compress with bz2
tar jcvf mydir.tar.bz2 mydir

# Create the archive for file mydir and compress with xz

mondwan

# redirect stdout
echo "hello" > a.out

# redirect stderr
echo "hello" 2> a.out

# redirect both of them
echo "hello" > a.out 2>&1
# shortcut
echo "hello" >& a.out

mondwan

# Look up hostname using dns
host linuxfoundation.org

# To look up name server interactively
nslookup linuxfoundation.org

# To look up domain name server information from the name server
dig linuxfoundation.org

mondwan

# Find filename with gcc under folder /usr
find /usr -name gcc

# Find directory based on filename gcc under folder /usr
find /usr -type d -name gcc

# Find file which modified today under current directory
find -type f -mtime 0

# Find file which filesize is zero