Sample Shell programs

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norm - set permissions as open as possible

chmod  u+rwx,go+rx-w  $*

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hide - as hidden as possible

chmod  u+rwx,go-rwx  $*

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semihide - just open enough as needed for Web

directories:

chmod  u+rwx,g-rwx,o+x-rw  $*

files (web pages, images, etc):

chmod  u+rwx,g-rwx,o+r-xw  $*

CGI scripts:

chmod  u+rwx,g-rwx,o+rx-w  $*

"norm" could of course replace all 3 if you don't mind granting more access than strictly necessary.

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rmifexists - silent repeated delete

e.g. Want to be able to repeatedly run:
rmifexists *.bak
and not get error message if no *.bak files found.

for i in $* do if test -f $i then rm $i fi done

• in fact, rm -f will do the job with no warnings
• rm

• rm -r (recursive rm)
• Don't type rm -rf /

Exercise

Why not:

        if test -f $*
        then
         rm $*
        fi

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myspace - which of my directories use the most space

cd $HOME
du | sort -n

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wipe - clean up editor backup files

rmifexists *%
rmifexists .*% 

rmifexists  *~
rmifexists .*~

rmifexists  *.bak
rmifexists .*.bak

rmifexists  *.BAK
rmifexists .*.BAK

Certainly easier than having to point-and-click each one.

Exercise

Write a recursive wipe.

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