shell script

• Tracing of execution

  set -x				# turn on tracing
  echo Hello world
  
  set +x				# turn off tracing
  echo World hello
  

• read from tty
  

  printf "Enter new passwd:"
  stty -echo			# turn off echoing of typed character
  read pass < /dev/tty
  printf "Enter again: "
  read pass2 < /dev/tty
  stty echo			# turn of the echoing of typed character
  

• find and grep
  

  find . -type f -print0 | xargs -0 -e grep -n -e
  find . \( -type f -exec grep -q BabelMain {} \;  \) -exec ls -ld {} \;
  

• select column

  lls --sort=size /tmp/*.nc | awk '//{print $5, $9}'
  

• get the path of command:

  dirname \$0
  

• support i-search-back in the TCSH
  add key binding by

  bindkey -b C-r i-search-back in the .cshrc file, and type C-r to activate the searching