root为用户改变登陆shell的脚本

      1 #!/bin/bash
      2
      3 #it is for root to change shell for users
      4 #wrote by badboy  2011.10.9
      5
      6 echo
      7 echo "####### It is for root to change users'shell ########"
      8 echo
      9 echo "####             Wrote by badboy                #####"
     10 echo "#####################################################"
     11 echo "##   for example : user=root shell=/bin/bash       ##"
     12 echo "#####################################################"
     13 read -p " enter the user name :" USER
     14 read -p " enter the shell for $USER :" SHELL
     15
     16 ######### to see if the user exit
     17
     18 if grep $USER /etc/passwd  1> /dev/null
     19   then
     20      echo
     21   else
     22       echo "System does not exit the user"
     23       exit
     24 fi
     25
     26 OIFS=$IFS
     27 IFS=:
     28 cat /etc/passwd |  while  read a b c d e f  OLDSHELL
     29                                 do
     30                                      if [ $a = $USER ]
     31                                         then
     32                                   echo "$a:$b:$c:$d:$e:$f:$SHELL" >>/etc/passwd.old
     33                                          else
     34                                 echo "$a:$b:$c:$d:$e:$f:$OLDSHELL" >>/etc/passwd.old
     35                                      fi
     36                                 done
     37 IFS=$OIFS
     38 cp /etc/passwd /etc/passwd.`date %y%m%d` #备份passwd
     39 cat /etc/passwd.old >/etc/passwd && cat /dev/null >/etc/passwd.old