Update
Merge branch 'master' of https://github.com/azatris/cs4218

# By Mingxia Liu (3) and others
# Via Mingxia Liu (1) and Silver Taza (1)
* 'master' of https://github.com/azatris/cs4218:
  Create common functions to reduce repeated code and modify some wrong test cases on fileutils
  Removed extra newline from Grep
  Updating cut
  Update all concatenateDirectory() function
  Fixing cat tool
  Updationg pipe and cut
  Try to deal with path in windows