Piping and redirecting output from one command or file to another

Piping entails sending standard output to the standard input of a linux command. Pipes are the primary power of using the command line. The can be used with sed, awk, perl, and python amoungst other tools to produce very specific behavior. To pipe the output to an new command place a '|' character between them.

Examples

command line pipe

wc -l * | sort -rn

pipes in for loops

 for f in `ls -al | awk '{print$9}' | sort`; 
 do 
    echo $f; 
    cp $f $f.bak; 
 done