pipes (and programs that like pipes)

• piping is redirection of stdout, instead of redirecting it to a file, you can redirect it to the input of a program, like connecting two pipes together. Use the $\vert$ character.
• you can redirect to any old program
• more, less

  ls /etc | less
  #whenever output is too big, you can use | less
  #use q to quit less, :n for next file, / to search
  

• tee: records stdout in a file, but also displays it to stdout (the screen)

        ls * |tee teeFile
        ls /etc/|tee teeFile2|less
  

• grep

   who | grep ijones
   ls /etc|grep net #see all files containing net
  

• xargs: run a command using stdin as the arguments to the command

  find . -print | xargs grep "mail" #like rgrep
  find . -name *.cpp |xargs less
   #as opposed to:
  find . -name *.cpp |less
  

bash (shell) builtins

• source: execute a shell script within this environment
• pushd, popd: change directories

   pushd . 
   cd 
   pwd
   popd