Shell errors

What is wrong with these Shell scripts?

 
 
# list files given in the argument:

ls$1 
 

 

# find processes and kill them:
# how do I know this script has never been run?

for i in 'ps -f | grep textedit' 
do 
 kill $i 
done 

 

# what caused this do you think?
  
Echo "some text" 
 
Ls -al 
 

 
 
cd /
cd ..



# list all files on disk, collect results in some output file:

cd /
ls -alR > outputfile.log



  
# substitute new text for old text in a number of files:

read OLDTEXT
read NEWTEXT

for i in $* 
do 
 sed -e "s|$OLDTEXT|$NEWTEXT|g" $i > $i 
done 

 
 
# how do I know this script has never been run?

find .   -name $1    > /dev/null 2> /dev /null



# how do I know this script has never been run?

echo "enter old text" 
read OLDTEXT 
 
echo "enter new text 
read NEWTEXT