{"id":5148,"date":"2015-08-17T08:58:05","date_gmt":"2015-08-17T00:58:05","guid":{"rendered":"http:\/\/rmohan.com\/?p=5148"},"modified":"2015-08-17T08:58:05","modified_gmt":"2015-08-17T00:58:05","slug":"shell-script-for-ssh-session","status":"publish","type":"post","link":"https:\/\/mohan.sg\/?p=5148","title":{"rendered":"shell script for ssh session"},"content":{"rendered":"
#!\/bin\/bash<\/code><\/div>\n
#\u00a0max_number_of_ssh_client\u00a0<\/code><\/div>\n
max_number_of_ssh_client=3<\/code><\/div>\n
<\/div>\n
#\u00a0lsof\u00a0is\u00a0essential<\/code><\/div>\n
if<\/code>\u00a0[[\u00a0!\u00a0-x\u00a0`<\/code>which<\/code>\u00a0lsof<\/code>`\u00a0]];\u00a0<\/code>then<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>yum\u00a0<\/code>install<\/code>\u00a0lsof<\/code>\u00a0-y<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>RETVAL=$?<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0[[\u00a0<\/code>\"$RETVAL\"<\/code>\u00a0-<\/code>ne<\/code>\u00a0\"0\"<\/code>\u00a0]];\u00a0<\/code>then<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>echo<\/code>\u00a0\"ERROR:\u00a0can\u00a0NOT\u00a0use\u00a0lsof\u00a0command,\u00a0please\u00a0check\u00a0your\u00a0internet\u00a0connection\u00a0or\u00a0install\u00a0lsof\u00a0by\u00a0manual!\u00a0\"<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>exit<\/code>\u00a0$RETVAL<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>fi<\/code><\/div>\n
else<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>#\u00a0TODO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>#\u00a0for\u00a0awk,\u00a0grep,\u00a0etc<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>echo<\/code>\u00a0\"SUCCESS:\u00a0This\u00a0shell\u00a0script\u00a0will\u00a0knock\u00a0out\u00a0extra\u00a0ssh\u00a0connection\u00a0\"<\/code><\/div>\n
fi<\/code><\/div>\n
<\/div>\n
#\u00a0a\u00a0main\u00a0worker<\/code><\/div>\n
#\u00a0loop<\/code><\/div>\n
while<\/code>\u00a0:\u00a0;\u00a0<\/code>do<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>ssh_port=`<\/code>netstat<\/code>\u00a0-anopt\u00a0|\u00a0<\/code>grep<\/code>\u00a0sshd\u00a0|\u00a0<\/code>awk<\/code>\u00a0'{print\u00a0$4}'<\/code>\u00a0|\u00a0<\/code>awk<\/code>\u00a0-F\u00a0<\/code>':'<\/code>\u00a0'{print\u00a0$2}'<\/code>\u00a0|\u00a0<\/code>grep<\/code>\u00a0-<\/code>v<\/code>\u00a0^$\u00a0|\u00a0<\/code>uniq<\/code>\u00a0`<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>ssh_clients=`<\/code>lsof<\/code>\u00a0-i:$ssh_port\u00a0|\u00a0<\/code>grep<\/code>\u00a0\\>\u00a0|\u00a0<\/code>awk<\/code>\u00a0'{print\u00a0$9}'<\/code>\u00a0|\u00a0<\/code>awk<\/code>\u00a0-F\u00a0<\/code>':'<\/code>\u00a0'{print\u00a0$(NF-1)}'<\/code>\u00a0|\u00a0<\/code>uniq<\/code>\u00a0|\u00a0<\/code>awk<\/code>\u00a0-F\u00a0<\/code>'>'<\/code>\u00a0'{print\u00a0$2}'<\/code>`<\/code><\/div>\n
<\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>for<\/code>\u00a0ssh_client\u00a0<\/code>in<\/code>\u00a0$ssh_clients;\u00a0<\/code>do<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>number_of_ssh_client=`<\/code>lsof<\/code>\u00a0-i:$ssh_port\u00a0|\u00a0<\/code>grep<\/code>\u00a0$ssh_client\u00a0|\u00a0<\/code>wc<\/code>\u00a0-l`<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0[[\u00a0$number_of_ssh_client\u00a0-gt\u00a0$max_number_of_ssh_client\u00a0]];\u00a0<\/code>then<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>number_pts=`w\u00a0-hs\u00a0|\u00a0<\/code>grep<\/code>\u00a0$ssh_client\u00a0|\u00a0<\/code>awk<\/code>\u00a0'{print\u00a0$2}'<\/code>\u00a0|\u00a0<\/code>awk<\/code>\u00a0-F\u00a0<\/code>'\/'<\/code>\u00a0'{print\u00a0$2}'<\/code>\u00a0|\u00a0<\/code>awk<\/code>\u00a0'BEGIN\u00a0{max=0}\u00a0{if\u00a0($1>max)\u00a0max=$1\u00a0fi}\u00a0END\u00a0{print\u00a0max}'<\/code>`<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>#\u00a0TODO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>#\u00a0another\u00a0solution\u00a0maybe\u00a0exist<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>#\u00a0kill\u00a0extra\u00a0logins<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>pkill\u00a0-<\/code>kill<\/code>\u00a0-t\u00a0pts\/$number_pts<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>if<\/code>\u00a0[[\u00a0$?\u00a0-<\/code>eq<\/code>\u00a00\u00a0]];\u00a0<\/code>then<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>echo<\/code>\u00a0\"SUCCESS:\u00a0extra\u00a0connections\u00a0\u00a0$ssh_client@pts\/$number_pts\u00a0has\u00a0been\u00a0knocked\u00a0out!\u00a0\"<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>else<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>echo<\/code>\u00a0\"WARNNING:\u00a0can\u00a0NOT\u00a0knock\u00a0out\u00a0extra\u00a0connections!\u00a0\"<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>fi<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>else<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>#\u00a0TODO<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>#\u00a0too\u00a0many\u00a0INFO\u00a0displayed<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>echo<\/code>\u00a0\"INFO:\u00a0number\u00a0of\u00a0ssh\u00a0connections\u00a0is\u00a0NORMAL!\u00a0\"<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>#\u00a0sleep\u00a01<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>sleep<\/code>\u00a01<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/code>fi<\/code><\/div>\n
\u00a0\u00a0\u00a0\u00a0<\/code>done<\/code><\/div>\n
<\/div>\n
done<\/code><\/div>\n","protected":false},"excerpt":{"rendered":"

#!\/bin\/bash # max_number_of_ssh_client max_number_of_ssh_client=3 # lsof is essential if [[ ! -x `which lsof` ]]; then yum install lsof -y RETVAL=$? if [[ “$RETVAL” -ne “0” ]]; then echo “ERROR: can NOT use lsof command, please check your internet connection or install lsof by manual! ” exit $RETVAL fi else # TODO # for awk, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[],"_links":{"self":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/5148"}],"collection":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5148"}],"version-history":[{"count":2,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/5148\/revisions"}],"predecessor-version":[{"id":5150,"href":"https:\/\/mohan.sg\/index.php?rest_route=\/wp\/v2\/posts\/5148\/revisions\/5150"}],"wp:attachment":[{"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5148"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5148"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mohan.sg\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5148"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}