File I/O Goodies

• Review - Dealing with standard error

  • echo "error" 2>&1 # prints stdout on stderr
  • touch /etc/motd 2>/dev/null #sends stderr to file
  • ls /nowhere >/dev/null 2>&1 #sends stderr same place as stdout, which in this case is /dev/null

• Safe temporary files:

  • NAME=`basename $0`
  • TMPFILE=`mktmp /tmp/$NAME.XXXXXX`
  • if [ ! -w $TMPFILE ]
  • then
    • echo "Temporary File Creation Failed" >&2
    • exit 1
  • fi
  • # do stuff, using $TMPFILE variable
  • rm -f $TMPFILE

• "Here" documents, multiple lines to stdin:

  • cat <<EOF
  • This is some
  • multi-line output.
  • EOF

Notes: