1. Create users user01-user10 in batches
#seq -w 10|sed -r "s/(.*)/useradd user\1/g"|bash
2. Analysis of -r and \1
-r, --regexp-extended
use extended regular expressions in the script
Indicates that extended regex can be used
\1 matches the first group in the regular, that is, matches the content in the first ()
The following case study
#vi test.txt
sxz23749237492384
zxs379427493279
SXZ932574534
#sed -n 's/^\([a-z A-Z]\{3\}\)\([0-9]\{3,\}\)/\2/p' test.txt
23749237492384
379427493279
932574534
Because special characters add escape characters, adding -r will cause an error instead
#sed -r -n's/^\([a-z A-Z]\{3\}\)\([0-9]\{3,\}\)/\2/p' test.txt
sed: -e expression #1, char 41: invalid reference \2 on `s' command's RHS
Just remove the escape characters
#sed -r -n 's/^([a-z A-Z]{3})([0-9]{2,})/\2/p' test.txt
23749237492384
379427493279
932574534
#tail -10 /etc/passwd
user01:x:5680:5680::/home/user01:/bin/bash
user02:x:5681:5681::/home/user02:/bin/bash
user03:x:5682:5682::/home/user03:/bin/bash
user04:x:5683:5683::/home/user04:/bin/bash
user05:x:5684:5684::/home/user05:/bin/bash
user06:x:5685:5685::/home/user06:/bin/bash
user07:x:5686:5686::/home/user07:/bin/bash
user08:x:5687:5687::/home/user08:/bin/bash
user09:x:5688:5688::/home/user09:/bin/bash
user10:x:5689:5689::/home/user10:/bin/bash
3. Add a random password for the user
3.1, random numbers
generate random numbers
RANDOM
exp：
Output 3 to 5 random numbers
echo $((RANDOM))
Generate seven random characters as letters and numbers
#cat /dev/urandom | head -1 | md5sum | head -c 7
7564fde
Generate seven random characters as alphanumeric plus special characters
#cat /dev/urandom | strings -n 7 | head -n 1
lAA'\H6z
3.2. Method 1
Modify user password using seven random characters, alphanumeric and special characters
#seq -w 10|sed -r 's#(.*)#key=`cat /dev/urandom|strings -n 7|head -n 1` ;echo $key|passwd --stdin user\1;echo "user\1:$key">> key.log#g'|bash
Changing password for user user01.
passwd: all authentication tokens updated successfully.
Changing password for user user02.
passwd: all authentication tokens updated successfully.
Changing password for user user03.
passwd: all authentication tokens updated successfully.
Changing password for user user04.
passwd: all authentication tokens updated successfully.
Changing password for user user05.
passwd: all authentication tokens updated successfully.
Changing password for user user06.
passwd: all authentication tokens updated successfully.
Changing password for user user07.
passwd: all authentication tokens updated successfully.
Changing password for user user08.
passwd: all authentication tokens updated successfully.
Changing password for user user09.
passwd: all authentication tokens updated successfully.
Changing password for user user10.
passwd: all authentication tokens updated successfully.
#cat key.log
user01: N> E} V3'z
user02:-,8W@c
user03: 3 {.h: 7V
user04: [SKIB $ &
user05: \: IsW @ c
user06:h"wlAtW#
user07: Pgo: t \)
user08:H_Xtj[\
user09: g)T#\V<
user10: eKDRJ0 = $
3.3. Method 2: Use chpasswd to change passwords in batches
chpasswd will batch read username and password pairs from standard input and use this information to update an existing set of
user
#echo user{01..10}:$((RANDOM))|tr " " "\n" > key.log
tr is to replace the preceding output spaces with newlines
#cat key.log
user01:12193
user02:32124
user03:26258
user04:4415
user05:24293
user06:10100
user07:13753
user08:3257
user09:24749
user10:15593
#chpasswd<key.log
Whether the test was successful
#su - user01
[user01@server ~]$ su - user02
Password:
[user02@server ~]$
3.4. The for loop command realizes batch deletion of users
#for USER in `cut -d: -f 1 key.log`;do userdel -r $USER;done
3.5. Script to create and modify passwords in batches for users
#vi useradd.sh
key=`cat /dev/urandom |strings -n 7 | head -n 1`
#!/bin/bash
#batch add users and passwd
for i in $(seq -w 10)
do
useradd user$i
key=`cat /dev/urandom |strings -n 7 | head -n 1`
echo $key|passwd --stdin user$i
echo "user$i:$key" >> key.log
done
#sh useradd.sh
Changing password for user user01.
passwd: all authentication tokens updated successfully.
Changing password for user user02.
passwd: all authentication tokens updated successfully.
Changing password for user user03.
passwd: all authentication tokens updated successfully.
Changing password for user user04.
passwd: all authentication tokens updated successfully.
Changing password for user user05.
passwd: all authentication tokens updated successfully.
Changing password for user user06.
passwd: all authentication tokens updated successfully.
Changing password for user user07.
passwd: all authentication tokens updated successfully.
Changing password for user user08.
passwd: all authentication tokens updated successfully.
Changing password for user user09.
passwd: all authentication tokens updated successfully.
Changing password for user user10.
passwd: all authentication tokens updated successfully.
#cat key.log
user01:@S_b~)(
user02: {WYci {) `
user03:yklE<&M
user04: O ~ I; q6k
user05: M*/X $ ioe;
user06:t$?|[aR_
user07:6`$chs=g>x
user08:5JGT4ydN+
user09:) FX (from |
user10:'R/rW)w
refer to:
http://blog.51cto.com/asmboy001/182290
http://bbs.chinaunix.net/thread-1387809-1-1.html
https://www.linuxidc.com/Linux/2015-08/122112.htm
http://blog.51cto.com/jackdady/1661781