Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
#!/bin/bash
# broken−link.sh
# Written by Lee bigelow
# Used with permission.
#A pure shell script to find dead symlinks and output them quoted
#so they can be fed to xargs and dealt with :)
#eg. broken−link.sh /somedir /someotherdir|xargs rm
#
#This, however, is a better method:
#
#find "somedir" −type l −print0|\
#xargs −r0 file|\
#grep "broken symbolic"|
#sed −e 's/^\|: *broken symbolic.*$/"/g'
#
#but that wouldn't be pure bash, now would it.
#Caution: beware the /proc file system and any circular links!
##############################################################
#If no args are passed to the script set directorys to search
#to current directory. Otherwise set the directorys to search
#to the agrs passed.
####################
[ $# −eq 0 ] && directorys=`pwd` || directorys=$@
#Setup the function linkchk to check the directory it is passed
#for files that are links and don't exist, then print them quoted.
#If one of the elements in the directory is a subdirectory then
#send that send that subdirectory to the linkcheck function.
##########
linkchk () {
for element in $1/*; do
[ −h "$element" −a ! −e "$element" ] && echo \"$element\"
[ −d "$element" ] && linkchk $element
# Of course, '−h' tests for symbolic link, '−d' for directory.
done
}
#Send each arg that was passed to the script to the linkchk function
#if it is a valid directoy. If not, then print the error message
#and usage info.
################
for directory in $directorys; do
if [ −d $directory ]
then linkchk $directory
else
echo "$directory is not a directory"
echo "Usage: $0 dir1 dir2 ..."
fi
done
exit 0
Example 29−1, Example 10−7, Example 10−3, Example 29−3, and Example A−2 also illustrate uses of the
file test operators.
Chapter 7. Tests 48