Linux设置长时间不操作自动断开连接

2021-07-29 02:59:53

简单梳理/etc/profile、/etc/bashrc、/etc/profile.d/、~/.bash_profile、~/.bashrc
CentOS7系统

1、/etc/profile

[root@centos7 ~]# cat /etc/profile

/etc/profile

System wide environment and startup programs, for login setup

Functions and aliases go in /etc/bashrc

It's NOT a good idea to change this file unless you know what you

are doing. It's much better to create a custom.sh shell script in

/etc/profile.d/ to make custom changes to your environment, as this

will prevent the need for merging in future updates.

pathmunge () {

case ":${PATH}:" in
    *:"$1":*)
        ;;
    *)
        if [ "$2" = "after" ] ; then
            PATH=$PATH:$1
        else
            PATH=$1:$PATH
        fi
esac

}

if [ -x /usr/bin/id ]; then

if [ -z "$EUID" ]; then
    # ksh workaround
    EUID=`/usr/bin/id -u`
    UID=`/usr/bin/id -ru`
fi
USER="`/usr/bin/id -un`"
LOGNAME=$USER
MAIL="/var/spool/mail/$USER"

Path manipulation

if [ "$EUID" = "0" ]; then

pathmunge /usr/sbin
pathmunge /usr/local/sbin

else

pathmunge /usr/local/sbin after
pathmunge /usr/sbin after

HOSTNAME=/usr/bin/hostname 2>/dev/null
HISTSIZE=1000
if [ "$HISTCONTROL" = "ignorespace" ] ; then

export HISTCONTROL=ignoreboth

else

export HISTCONTROL=ignoredups

export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL

By default, we want umask to get set. This sets it for login shell

Current threshold for system reserved uid/gids is 200

You could check uidgid reservation validity in

/usr/share/doc/setup-*/uidgid file

if [ $UID -gt 199 ] && [ "/usr/bin/id -gn" = "/usr/bin/id -un" ]; then

umask 002

else

umask 022

for i in /etc/profile.d/*.sh /etc/profile.d/sh.local ; do

if [ -r "$i" ]; then
    if [ "${-#*i}" != "$-" ]; then
        . "$i"
    else
        . "$i" >/dev/null
    fi
fi

done

unset i
unset -f pathmunge
2、 /etc/bashrc

[root@centos7 ~]# cat /etc/bashrc

/etc/bashrc

System wide functions and aliases

Environment stuff goes in /etc/profile

It's NOT a good idea to change this file unless you know what you

are doing. It's much better to create a custom.sh shell script in

/etc/profile.d/ to make custom changes to your environment, as this

will prevent the need for merging in future updates.

are we an interactive shell?

if [ "$PS1" ]; then
if [ -z "$PROMPT_COMMAND" ]; then

case $TERM in
xterm*|vte*)
  if [ -e /etc/sysconfig/bash-prompt-xterm ]; then
      PROMPT_COMMAND=/etc/sysconfig/bash-prompt-xterm
  elif [ "${VTE_VERSION:-0}" -ge 3405 ]; then
      PROMPT_COMMAND="__vte_prompt_command"
  else
      PROMPT_COMMAND='printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"'
  fi
  ;;
screen*)
  if [ -e /etc/sysconfig/bash-prompt-screen ]; then
      PROMPT_COMMAND=/etc/sysconfig/bash-prompt-screen
  else
      PROMPT_COMMAND='printf "\033k%s@%s:%s\033\\" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"'
  fi
  ;;
*)
  [ -e /etc/sysconfig/bash-prompt-default ] && PROMPT_COMMAND=/etc/sysconfig/bash-prompt-default
  ;;
esac

fi
# Turn on parallel history
shopt -s histappend
history -a
# Turn on checkwinsize
shopt -s checkwinsize
[ "$PS1" = "\\s-\\v\\\$ " ] && PS1="[u@h W]\$ "
# You might want to have e.g. tty in prompt (e.g. more virtual machines)
# and console windows
# If you want to do so, just add e.g.
# if [ "$PS1" ]; then
# PS1="[u@h:l W]\$ "
# fi
# to your custom modification shell script in /etc/profile.d/ directory
fi

if ! shopt -q login_shell ; then # We're not a login shell

# Need to redefine pathmunge, it get's undefined at the end of /etc/profile
pathmunge () {
    case ":${PATH}:" in
        *:"$1":*)
            ;;
        *)
            if [ "$2" = "after" ] ; then
                PATH=$PATH:$1
            else
                PATH=$1:$PATH
            fi
    esac
}

# By default, we want umask to get set. This sets it for non-login shell.
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
# /usr/share/doc/setup-*/uidgid file
if [ $UID -gt 199 ] && [ "`/usr/bin/id -gn`" = "`/usr/bin/id -un`" ]; then
   umask 002
else
   umask 022
fi

SHELL=/bin/bash
# Only display echos from profile.d scripts if we are no login shell
# and interactive - otherwise just process them to set envvars
for i in /etc/profile.d/*.sh; do
    if [ -r "$i" ]; then
        if [ "$PS1" ]; then
            . "$i"
        else
            . "$i" >/dev/null
        fi
    fi
done

unset i
unset -f pathmunge

vim:ts=4:sw=4

3、~/.bash_profile

.bash_profile

Get the aliases and functions

if [ -f ~/.bashrc ]; then

    . ~/.bashrc

User specific environment and startup programs

PATH=$PATH:$HOME/bin

export PATH
4、~/.bashrc

.bashrc

User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

Source global definitions

if [ -f /etc/bashrc ]; then

    . /etc/bashrc

fi
5、/etc/profile.d/

[root@centos7 ~]# ls -al /etc/profile.d/
total 84
drwxr-xr-x. 2 root root 4096 May 22 09:47 .
drwxr-xr-x. 75 root root 8192 May 22 10:22 ..
-rw-r--r--. 1 root root 771 Apr 11 13:09 256term.csh
-rw-r--r--. 1 root root 841 Apr 11 13:09 256term.sh
-rw-r--r--. 1 root root 196 Mar 25 2017 colorgrep.csh
-rw-r--r--. 1 root root 201 Mar 25 2017 colorgrep.sh
-rw-r--r--. 1 root root 1741 Apr 11 04:20 colorls.csh
-rw-r--r--. 1 root root 1606 Apr 11 04:20 colorls.sh
-rw-r--r--. 1 root root 80 Apr 11 12:18 csh.local
-rw-r--r--. 1 root root 1706 Apr 11 13:09 lang.csh
-rw-r--r--. 1 root root 2703 Apr 11 13:09 lang.sh
-rw-r--r--. 1 root root 123 Jul 31 2015 less.csh
-rw-r--r--. 1 root root 121 Jul 31 2015 less.sh
-rw-r--r-- 1 root root 148 May 22 09:47 path.sh
-rw-r--r--. 1 root root 81 Apr 11 12:18 sh.local
-rw-r--r--. 1 root root 105 Apr 11 07:54 vim.csh
-rw-r--r-- 1 root root 269 May 22 09:42 vim.sh
-rw-r--r--. 1 root root 164 Jan 28 2014 which2.csh
-rw-r--r--. 1 root root 169 Jan 28 2014 which2.sh
/etc/profile

|- System wide environment and startup programs, for login setup

|- 用于登录设置的全系统环境和启动程序

/etc/bashrc

|- System wide functions and aliases

|- 系统范围的函数和别名

/etc/profile.d/

|- It's much better to create a custom.sh shell script in /etc/profile.d/ to make custom changes to your environment, as this will prevent the need for merging in future updates.

|- 最好在/etc/profile.d/中创建一个custom.Shell脚本，以便对环境进行自定义更改，因为这将避免在将来的更新中合并。

~/.bash_profile

|- User specific environment and startup programs

|- 用户特定环境和启动程序

~/.bashrc

|- User specific aliases and functions

|- 用户特定别名和函数

系统启动时加载 /etc/profile -> 内部加载 /etc/profile.d/ 路径下的*.sh脚本；

用户登录时加载 ~/.bash_profile -> 内部加载 ~/.bashrc -> 内部加载 /etc/bashrc -> 内部加载 /etc/profile.d/ 路径下的*.sh脚本；

用户退出时加载 ~/.bash_logout ；

结论：

在 /etc/profile 中配置系统变量；

在 ~/.bash_profile 中配置用户变量；

SSH连接linux时，长时间不操作就断开的解决方案（增强版）
1、第一次尝试失败
修改/etc/ssh/sshd_config文件，

找到

ClientAliveInterval 0

ClientAliveCountMax 3

并将注释符号（"#"）去掉,

将ClientAliveInterval对应的0改成60,

ClientAliveInterval指定了服务器端向客户端请求消息的时间间隔, 默认是0, 不发送.
ClientAliveInterval 60表示每分钟发送一次, 然后客户端响应, 这样就保持长连接了.
ClientAliveCountMax, 使用默认值3即可.

ClientAliveCountMax表示服务器发出请求后客户端没有响应的次数达到一定值, 就自动断开.
正常情况下, 客户端不会不响应.

重起sshd服务：

service sshd restart

依旧没多久就断开窗口

2、第二次尝试成功
为了增强Linux系统的安全性，我们需要在用户输入空闲一段时间后自动断开，这个操作可以由设置TMOUT值来实现。将以下字段加入到/etc/profile 中即可（对所有用户生效）。

export TMOUT=900 # 设置900秒内用户无操作就字段断开终端

readonly TMOUT # 将值设置为readonly 防止用户更改

注意：设置了readonly 之后在当前shell下是无法取消的，需要先将/etc/profile 中设置readonly行注释起来或直接删除，logout 后重新login 。

$ export TMOUT=900

$ readonly TMOUT

$ unset TMOUT

-bash: unset: TMOUT: cannot unset: readonly variable

vim /etc/profile.d/tmout.sh

TMOUT=300

#readonly  TMOUT

export  TMOUT

source /etc/profile.d/tmout.sh

TMOUT:设置超时时间

readonly:设置变量为只读

码农公寓

/etc/profile

System wide environment and startup programs, for login setup

Functions and aliases go in /etc/bashrc

It's NOT a good idea to change this file unless you know what you

are doing. It's much better to create a custom.sh shell script in

/etc/profile.d/ to make custom changes to your environment, as this

will prevent the need for merging in future updates.

Path manipulation

By default, we want umask to get set. This sets it for login shell

Current threshold for system reserved uid/gids is 200

You could check uidgid reservation validity in

/usr/share/doc/setup-*/uidgid file

/etc/bashrc

System wide functions and aliases

Environment stuff goes in /etc/profile

It's NOT a good idea to change this file unless you know what you

are doing. It's much better to create a custom.sh shell script in

/etc/profile.d/ to make custom changes to your environment, as this

will prevent the need for merging in future updates.

are we an interactive shell?

vim:ts=4:sw=4

.bash_profile

Get the aliases and functions

User specific environment and startup programs

.bashrc

User specific aliases and functions

Source global definitions

在 ~/.bash_profile 中配置用户变量；

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