Advanced Bash−Scripting Guide

#+ it is necessary to substitute for the normal "/" delimiter
#+ because "/" happens to be one of the characters filtered out.
# Failure to do so gives an error message (try it).
done
exit 0
Advanced Bash−Scripting Guide
# Exercise (easy):
# −−−−−−−−−−−−−−−
# Convert this script to taking command−line parameters
#+ for $directory and $fstring.
The output of a for loop may be piped to a command or commands.
Example 10−10. Listing the symbolic links in a directory
#!/bin/bash
# symlinks.sh: Lists symbolic links in a directory.
directory=${1−`pwd`}
# Defaults to current working directory,
#+ if not otherwise specified.
# Equivalent to code block below.
# −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
# ARGS=1 # Expect one command−line argument.
#
# if [ $# −ne "$ARGS" ] # If not 1 arg...
# then
# directory=`pwd` # current working directory
# else
# directory=$1
# fi
# −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
echo "symbolic links in directory \"$directory\""
for file in "$( find $directory −type l )"
do
echo "$file"
done | sort
# −type l = symbolic links
# Otherwise file list is unsorted.
# As Dominik 'Aeneas' Schnitzer points out,
#+ failing to quote $( find $directory −type l )
#+ will choke on filenames with embedded whitespace.
# Even this will only pick up the first field of each argument.
exit 0
The stdout of a loop may be redirected to a file, as this slight modification to the previous example
shows.
Example 10−11. Symbolic links in a directory, saved to a file
#!/bin/bash
# symlinks.sh: Lists symbolic links in a directory.
Chapter 10. Loops and Branches 108