Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
}
zz=`expr $zz + 1` # ==> Increment zz.
done
if [ −L "$dir" ] ; then # ==> If directory is a symbolic link...
echo "+−−−$dir" `ls −l $dir | sed 's/^.*'$dir' //'`
# ==> Display horiz. connector and list directory name, but...
# ==> delete date/time part of long listing.
else
echo "+−−−$dir"
# ==> Display horizontal connector symbol...
# ==> and print directory name.
if cd "$dir" ; then # ==> If can move to subdirectory...
fi
deep=`expr $deep + 1` # ==> Increment depth.
search # with recursivity ;−)
# ==> Function calls itself.
numdirs=`expr $numdirs + 1` # ==> Increment directory count.
fi
fi
done
cd .. # ==> Up one directory level.
if [ "$deep" ] ; then # ==> If depth = 0 (returns TRUE)...
swfi=1
# ==> set flag showing that search is done.
fi
deep=`expr $deep − 1` # ==> Decrement depth.
# − Main −
if [ $# = 0 ] ; then
cd `pwd` # ==> No args to script, then use current working directory.
else
cd $1 # ==> Otherwise, move to indicated directory.
fi
echo "Initial directory = `pwd`"
swfi=0 # ==> Search finished flag.
deep=0 # ==> Depth of listing.
numdirs=0
zz=0
while [ "$swfi" != 1 ] # While flag not set...
do
search # ==> Call function after initializing variables.
done
echo "Total directories = $numdirs"
exit 0
# ==> Challenge: try to figure out exactly how this script works.
Noah Friedman gave permission to use his string function script, which essentially reproduces some of the
C−library string manipulation functions.
Example A−19. string functions: C−like string functions
#!/bin/bash
# string.bash −−− bash emulation of string(3) library routines
# Author: Noah Friedman
# ==> Used with his kind permission in this document.
# Created: 1992−07−01
# Last modified: 1993−09−29
# Public domain
Appendix A. Contributed Scripts 391