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【Linux教程】Linux shell sudo 命令使用介绍

Linux shell sudo命令以系统管理者的身份执行指令,也就是,经由 sudo 所执行的指令就好像是 root 亲自执行。

使用权限:/etc/sudoers 中有出现的使用者。

sudo 命令语法格式

sudo -V
sudo -h
sudo -l
sudo -v
sudo -k
sudo -s
sudo -H
sudo [ -b ] [ -p prompt ] [ -u username/#uid] -s
sudo command

选项

-V
显示版本编号
-h
会显示版本编号及指令的使用方式说明
-l
显示出自己(执行 sudo 的使用者)的权限
-v
因为 sudo 在第一次执行时或是在 N 分钟内没有执行(N 预设为五)会问密码,这个参数是重新做一次确认,如果超过 N 分钟,也会问密码
-k
将会强迫使用者在下一次执行 sudo 时问密码(不论有没有超过 N 分钟)
-b
将要执行的指令放在背景执行
-p prompt
可以更改问密码的提示语,其中 %u 会代换为使用者的帐号名称, %h 会显示主机名称
-u username/#uid
不加此参数,代表要以 root 的身份执行指令,而加了此参数,可以以 username 的身份执行指令(#uid 为该 username 的使用者号码)
-s
执行环境变数中的 SHELL 所指定的 shell ,或是 /etc/passwd 里所指定的 shell
-H
将环境变数中的 HOME (家目录)指定为要变更身份的使用者家目录(如不加 -u 参数就是系统管理者 root )
command
要以系统管理者身份(或以 -u 更改为其他人)执行的指令

范例

sudo 命令使用

[yufei@locahost ~]$ sudo ls
[sudo] password for yufei:
yufei is not in the sudoers file. This incident will be reported.

指定用户执行命令

[yufei@localhost shell]$ sudo -u root ls -l
total 16
-rw-r--r--. 1 root root  93 Sep 19 11:43 demo1.sh
-rwxr-xr-x. 1 root root 219 Sep 19 11:43 demo2.sh
-rw-r--r--. 1 root root   0 Sep 19 16:06 demo.cpp
-rw-r--r--. 1 root root 122 Sep 19 11:43 demo.sh
-rw-r--r--. 1 root root   0 Sep 19 16:06 main.c
-rw-r--r--. 1 root root 113 Sep 21 00:14 w.sh

显示sudo设置

[yufei@localhost shell]$ sudo -L //显示sudo设置
Available options in a sudoers ``Defaults'' line:
syslog: Syslog facility if syslog is being used for logging
syslog_goodpri: Syslog priority to use when user authenticates successfully
syslog_badpri: Syslog priority to use when user authenticates unsuccessfully
long_otp_prompt: Put OTP prompt on its own line
ignore_dot: Ignore '.' in $PATH
mail_always: Always send mail when sudo is run
mail_badpass: Send mail if user authentication fails
mail_no_user: Send mail if the user is not in sudoers
mail_no_host: Send mail if the user is not in sudoers for this host
mail_no_perms: Send mail if the user is not allowed to run a command
tty_tickets: Use a separate timestamp for each user/tty combo
lecture: Lecture user the first time they run sudo
lecture_file: File containing the sudo lecture
authenticate: Require users to authenticate by default
root_sudo: Root may run sudo
log_host: Log the hostname in the (non-syslog) log file
log_year: Log the year in the (non-syslog) log file
shell_noargs: If sudo is invoked with no arguments, start a shell
set_home: Set $HOME to the target user when starting a shell with -s
always_set_home: Always set $HOME to the target user's home directory
path_info: Allow some information gathering to give useful error messages
fqdn: Require fully-qualified hostnames in the sudoers file
insults: Insult the user when they enter an incorrect password
requiretty: Only allow the user to run sudo if they have a tty
env_editor: Visudo will honor the EDITOR environment variable
rootpw: Prompt for root's password, not the users's
runaspw: Prompt for the runas_default user's password, not the users's
targetpw: Prompt for the target user's password, not the users's
use_loginclass: Apply defaults in the target user's login class if there is one
set_logname: Set the LOGNAME and USER environment variables
stay_setuid: Only set the effective uid to the target user, not the real uid
preserve_groups: Don't initialize the group vector to that of the target user
loglinelen: Length at which to wrap log file lines (0 for no wrap)
timestamp_timeout: Authentication timestamp timeout
passwd_timeout: Password prompt timeout
passwd_tries: Number of tries to enter a password
umask: Umask to use or 0777 to use user's
logfile: Path to log file
mailerpath: Path to mail program
mailerflags: Flags for mail program
mailto: Address to send mail to
mailfrom: Address to send mail from
mailsub: Subject line for mail messages
badpass_message: Incorrect password message
timestampdir: Path to authentication timestamp dir
timestampowner: Owner of the authentication timestamp dir
exempt_group: Users in this group are exempt from password and PATH requirements
passprompt: Default password prompt
passprompt_override: If set, passprompt will override system prompt in all cases.
...

以 root 权限执行上一条命令

[yufei@localhost shell]$ sudo !!
total 16
-rw-r--r--. 1 root root  93 Sep 19 11:43 demo1.sh
-rwxr-xr-x. 1 root root 219 Sep 19 11:43 demo2.sh
-rw-r--r--. 1 root root   0 Sep 19 16:06 demo.cpp
-rw-r--r--. 1 root root 122 Sep 19 11:43 demo.sh
-rw-r--r--. 1 root root   0 Sep 19 16:06 main.c
-rw-r--r--. 1 root root 113 Sep 21 00:14 w.sh

以特定用户身份进行编辑文本

以 root 用户身份编辑 /data/www 下的 index.html 文件

[yufei@localhost shell]$ sudo -u root vi /data/www/cn_twle_www/index.html

列出目前的权限

[yufei@localhost ~]$ sudo -l

列出 sudo 的版本资讯

[yufei@localhost ~]$ sudo -V

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