sh-2.02$ cat simple
Here is a file containing some words.
A total of 3 lines have been used.
This line makes the last one right.
sh-2.02$ c=3
sh-2.02$ sed -n /A/,"$c"p simple
A total of 3 lines have been used.
This line makes the last one right.
sh-2.02$ expr $c + 4
7
sh-2.02$ c=`wc -l simple`
sh-2.02$ echo $c
3 simple
sh-2.02$ expr $c + 4
expr: syntax error
sh-2.02$ sed -n /A/,"$c"p simple