ex3.sh

Shall高级编程

#!/bin/bash

# This is a simple script that removes blank lines from a file.
# No argument checking.
#
# You might wish to add something like:
#
# E_NOARGS=65
# if [ -z "$1" ]
# then
#  echo "Usage: `basename $0` target-file"
#  exit $E_NOARGS
# fi


# Same as
#    sed -e '/^$/d' filename
# invoked from the command line.

sed -e /^$/d "$1"
#  The '-e' means an "editing" command follows (optional here).
#  '^' is the beginning of line, '$' is the end.
#  This match lines with nothing between the beginning and the end,
#+ blank lines.
#  The 'd' is the delete command.

#  Quoting the command-line arg permits
#+ whitespace and special characters in the filename.

#  Note that this script doesn't actually change the target file.
#  If you need to do that, redirect its output.

exit 0