Ubuntu 20.04 

在使用 Ubuntu 系统 root 用户创建一个普通用户后，发现 Shell 命令行显示很简单，不显示用户名、hostname等信息。

root@ecszjk:~# useradd test -m
root@ecszjk:~#
root@ecszjk:~#
root@ecszjk:~# su – test
$
$ id
uid=1001(test) gid=1001(test) groups=1001(test)
$

这个问题是由于新创建的用户默认使用的是 /bin/sh 而不是 /bin/bash，两种不同规范的 Shell 不一样。

可以从 /etc/passwd 中查看账号的 Shell 命令，从 /etc/passwd 中可以看到默认创建的用户使用的是 /bin/sh，而 root 用户使用的是 /bin/bash。

$ cat /etc/passwd
root:x:0:0:root:/root:/bin/bash
…
test:x:1001:1001::/home/test:/bin/sh

使用 root 用户编辑 /etc/passwd 文件，将对应用户的 Shell 改为 /bin/bash，并保存退出

使用 vim 的命令模式输入 :wq 保存并退出。

使用 root 用户执行 usermod 命令为对应用户更新 Shell

root@ecszjk:~#
root@ecszjk:~# usermod test -s /bin/bash
root@ecszjk:~# cat /etc/passwd
root:x:0:0:root:/root:/bin/bash
…
test:x:1001:1001::/home/test:/bin/bash

1、useradd 用法

root@ecszjk:/etc# useradd –help
Usage: useradd [options] LOGINuseradd -Duseradd -D [options]
Options:–badnames                do not check for bad names-b, –base-dir BASE_DIR       base directory for the home directory of thenew account–btrfs-subvolume-home    use BTRFS subvolume for home directory-c, –comment COMMENT         GECOS field of the new account-d, –home-dir HOME_DIR       home directory of the new account-D, –defaults                print or change default useradd configuration-e, –expiredate EXPIRE_DATE  expiration date of the new account-f, –inactive INACTIVE       password inactivity period of the new account-g, –gid GROUP               name or ID of the primary group of the newaccount-G, –groups GROUPS           list of supplementary groups of the newaccount-h, –help                    display this help message and exit-k, –skel SKEL_DIR           use this alternative skeleton directory-K, –key KEY=VALUE           override /etc/login.defs defaults-l, –no-log-init             do not add the user to the lastlog andfaillog databases-m, –create-home             create the user’s home directory-M, –no-create-home          do not create the user’s home directory-N, –no-user-group           do not create a group with the same name asthe user-o, –non-unique              allow to create users with duplicate(non-unique) UID-p, –password PASSWORD       encrypted password of the new account-r, –system                  create a system account-R, –root CHROOT_DIR         directory to chroot into-P, –prefix PREFIX_DIR       prefix directory where are located the /etc/* files-s, –shell SHELL             login shell of the new account-u, –uid UID                 user ID of the new account-U, –user-group              create a group with the same name as the user-Z, –selinux-user SEUSER     use a specific SEUSER for the SELinux user mapping–extrausers              Use the extra users database

2、/bin/sh 与 /bin/bash 的区别

#!/bin/sh与#!/bin/bash的区别 - myhesir - 博客园