Shell Programming and Scripting

sed -i 's/^Hello1/hi/g' File1

sed -i 's/^$ns_/$ns/g'~/Downloads/Project/p0s5n15_$i.tcl

sed: -e expression #1, char 18: unknown option to `s'
sed: -e expression #1, char 18: unknown option to `s'
sed: -e expression #1, char 18: unknown option to `s'

sed -i 's/^$ns_/$ns/g' ~/Downloads/Project/p0s5n15_$i.tcl

for i in 1 2 
do 
sed -i 's/hello/helloi/g' ~/Downloads/Project/file$i.tcl
done

for i in 1 2 
do 
    sed -i "s/hello/hello${i}/g" ~/Downloads/Project/file$i.tcl
done

sed -i "s/filename/"~/Downloads/Project/${i}.tcl"/g" ~/Downloads/Project/p0s5n15_$i.tcl;