ex65.sh

Shall高级编程

#!/bin/bash

#  delete.sh, not-so-cunning file deletion utility.
#  Usage: delete filename

E_BADARGS=65

if [ -z "$1" ]
then
  echo "Usage: `basename $0` filename"
  exit $E_BADARGS  # No arg? Bail out.
else  
  file=$1          # Set filename.
fi  


[ ! -f "$file" ] && echo "File \"$file\" not found. \
Cowardly refusing to delete a nonexistent file."
# AND LIST, to give error message if file not present.
# Note echo message continued on to a second line with an escape.

[ ! -f "$file" ] || (rm -f $file; echo "File \"$file\" deleted.")
# OR LIST, to delete file if present.

# Note logic inversion above.
# AND LIST executes on true, OR LIST on false.

exit 0