bash arrays, removing one path component at a time

README.md

I had a problem with chmod not working. It seemed to be related to something in my path. I spent more time on this script to test removing individual path components than I would have done brute forcing it. And it didn't tell me the problem, as it was related to at least two path entries.

However, this script does demonstrate something or other about working with arrays in Bash. Mostly it demonstrates how awkward the exercise is.

testPathComponents.bash

#!/bin/bash

#I had a problem with chmod not working It seemed to be related to my
#path. I spent more time on this script to test removing individual
#path components than I would have done brute forcing it. And it
#dodn't tell me the problem, as it was related to two path entries.

#However, this script does demonstrate something or other about
#working with arrays in Bash. Mostly it demonstrates how awkward the
#exercise is.

CANONICAL_PATH="/Library/Frameworks/EPD64.framework/Versions/Current/bin:/Library/Frameworks/Python.framework/Versions/Current/bin:~/android-sdk-macosx/tools:~/android-sdk-macosx/platform-tools:/Library/Frameworks/Python.framework/Versions/Current/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/texbin:/usr/X11/bin"

IFS=":"
set -- $CANONICAL_PATH
NUMBER="$#"
unset IFS
unset PATH_COMPONENTS
#0 based arrays, but the "set" builten sets starting at $1 and the {..}
#operator is inclusive. WTF.
for i in $(eval echo {1..$#}); do 
    eval "PATH_COMPONENTS[$i]=\${$i}"
done

for i in $(eval echo {1..$NUMBER}); do
    NEWPATH=( "${PATH_COMPONENTS[@]}" )
    unset NEWPATH[$(( $i - 1 ))]
    IFS=":"
    echo ${PATH_COMPONENTS[$i]}
    PATH="${NEWPATH[*]}"
    unset IFS
    rm -f testscript
    cat >testscript <<EOF
#!/bin/bash
echo "hello, world"
EOF
    chmod a+x testscript
    ls -l testscript
done

PATH=${CANONICAL_PATH}