how to execute bash scripts via cgi -

i'm trying call bash script within webpage page using cgi. have partially working in echo commands appear work other commands don't.

i'm using lighttpd , have file cgi.sh, calls demo_start.sh

cat /srv/http/cgi.sh

#!/bin/bash . includes/srv/http/demo_start.sh /usr/bin/bash /srv/http/demo_start.sh 

cat /srv/http/demo_start.sh

#!/bin/bash printf "content-type: text/plain\n\n"  ip route 1 | awk '{print $nf;exit}'>/srv/http/ip.txt file="/srv/http/ip.txt" ip_address=$(cat ${file})  echo ${ip_address}  file="/srv/http/demo_count.txt" count=$(cat ${file})  ((count++)) echo ${count} > ${file}  echo demo started ${count} times  sed -i".bak" '$d' /srv/http/index.html sed -i '$ <a href="http://'${ip_address}':'${count}'">start demo</a<br/>' /srv/http/index.html 

when access http://localhost/cgi.sh

172.27.103.31

demo started 8056 times

if refresh get

172.27.103.31

demo started 8057 times

all echo commands working , reads , write counter file correctly. sed commands not run index.html isn't updated.

if sh demo_start.sh bash prompt works correctly. how commands run when call script via cgi?

thanks in advance