Assignment
Write a shell script to concatenate lists together, and output the resulting list. Do not include any argument that is a sub-list of the entire list. (The script will clean the list of any redundant items.) You must preserve the original order of the list. Remember to account for the following situations:
• a : at the beginning of the list is the same as a . at the beginning of the "list" (:/bin is the same a .:/bin)
• a :: any where in the list is the same as :.: (/bin::/etc is the same as (/bin:.:/etc)
• a : at the end of the list is the same a :. ( /bin: is the same as /bin:. )
• Project usings temporary files will not be graded.
• The input to the script will be color or space separated lists and the output will be a colon separated list with the orignal order preserved and all redunant items removed.
USAGE: clean_list list ....
Where list a a colon or whitespace separated list.
Examples:
prompt>clean_list a a:b a:b:c :x: y:z
a:b:c:.:x:y:z
prompt>clean_list /bin:/usr/bin:/usr/openwin/bin /usr/bin:/usr/etc:/etc: /usr/bin/X11 .:/bin
/bin:/usr/bin:/usr/openwin/bin:/usr/etc:/etc:.:/usr/bin/X11
prompt>clean_listapple:orange:apple pear orange peach
apple:orange:pear:peach
REMEMBER TO HANDLE THE SPECIAL CASES OF LEADING :, A ::, AND A TRAILING :
• Example Script very similar to Project 2
The following script is very similar to project 2; however, the major differences are is that it works with a single variable, not the command line arguments and the script tests to see if directories exist (not needed for project 2). Also, for project 2, each positional parameter, can be a special case, where : at the begining of a paramter is really .:, a :: in a parameter is really :.:, and a : at the end of a parameter is :.
You should run this script and see what happens and then modify it to meet the requirements for project 2
That is the tricky part, becase A:B :C --> is A:B:.:C but the code below won't handle that case.
#!/bin/sh
NP=
for P in `echo $PATH | sed -e 's/^:/.:/' -e 's/::/:.:/' -e 's/:$/:./' -e 's/:/ /g'`
do
case $NP in
"")
if [ -d "$P" ]
then
NP="$P"
fi
;;
$P|$P:*|*:$P:*|*:$P)
continue
;;
*)
if [ -d "$P" ]
then
NP="$NP:$P"
fi
;;
esac
done
echo $NP
Attachment:- Linux-Assignment.zip