mksu

#!/usr/bin/env expect --
# vim:ts=4:sw=4:expandtab

#######################################################################
# NAME
#     mksu - a toy for su with command
#
# SYNOPSIS
#     mksu username password command
#
# AUTHORS
#     neiku project <ku7d@qq.com> 
#
# SEE ALSO
#     su
#     expect --help
#
# VERSION
#     2016/06/18: 支持使用su命令切换用户后执行命令
#     2017/01/16: 支持跨平台
#                 - 通过env程序+PATH变量动态查询bash，控制权
#                   、准确性都得到保障
#
#######################################################################

set username "[lindex $argv 0]"
set password "[lindex $argv 1]"
set command  "[lindex $argv 2]"
set timeout  -1

if { $command == "" } {
    send_user "usage: mksu username password command\n"
    exit
}

if { $password == "" } {
    # when MKX_MKSU_PASSWORD not exist
    # expect will throw expection (to exit)
    # now we catch and ignore it (password still empty)
    catch { set password "$env(MKX_MKSU_PASSWORD)" }
}

send_user "run '$command' with $username\n"

set env(LC_CTYPE) en
spawn -noecho su $username --command=$command
expect {
    # ask for password
    "*assword:" {
        send "$password\r"
    }

    # for command done
    eof {
        exit
    }

    # error occurred, then exit
    "su" {
        exit
    }
}

expect eof
exit