生成临时文件

可以使用 mktemp 命令生成 tmp 文件，mktemp -d 生成临时目录，避免临时目录重复使用的问题

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#!/bin/bash
tmp_file="$(mktemp)"
tmp_folder="$(mktemp -d)"

echo $tmp_file
echo $tmp_folder

tmp 目录定时清理

这个是由 systemd 的几个模块实现的， 在 centos7 中：

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systemd-tmpfiles-setup.service  ：Create Volatile Files and Directories
systemd-tmpfiles-setup-dev.service：Create static device nodes in /dev
systemd-tmpfiles-clean.service ：Cleanup of Temporary Directories

配置文件也有 3 个地方：

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/etc/tmpfiles.d/*.conf
/run/tmpfiles.d/*.conf
/usr/lib/tmpfiles.d/*.conf

/tmp 目录的清理规则主要取决于 /usr/lib/tmpfiles.d/tmp.conf 文件的设定，默认的配置内容为：

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#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

# See tmpfiles.d(5) for details

# Clear tmp directories separately, to make them easier to override
v /tmp 1777 root root 10d
v /var/tmp 1777 root root 30d

# Exclude namespace mountpoints created with PrivateTmp=yes
x /tmp/systemd-private-%b-*
X /tmp/systemd-private-%b-*/tmp
x /var/tmp/systemd-private-%b-*
X /var/tmp/systemd-private-%b-*/tmp

如你不想让系统自动清理/tmp 下以 tomcat 开头的目录，那么增加下面这条内容到配置文件中即可：

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x /tmp/tomcat.*