Linux--shell Programming (vi) using scripting options and combination condition testing

Write a script:

1. Add 10 users user1 to User10, password with user name, but only if the user does not exist to add;

#!/bin/bash# forIinch{1..Ten}; Do    if!IDUser$i &>/dev/NULL; ThenUseradd user$iEcho "user$i"|passwd--stdin user$iElse        Echo "User$i exists"        fi Done

Delete the above 10 users

#!/bin/bash# forIinch{1..Ten}; Do    if IDUser$i &>/dev/NULL; ThenUserdel-r user$i &>/dev/nullEcho "user$i deleted"    Else        Echo "user$i NOT EXISTS"    fi Done

Extension: Adds or deletes a specified number of users based on input parameters,

#!/bin/Bash2 #  3 if[$#-lt1]; Then  4     Echo "Usage:no ARGs"  5 fi  6 if[ $1=="--add"]; Then  7  forIinch`Echo$2|sed 's/,//g'`; Do  8     if ID$I &>/dev/NULL; Then  9        Echo "$I exists" Ten     Else  OneUseradd $I A         Echo$I |passwd--stdin $I &>/dev/NULL  -         Echo "Add $I finished"  -     fi  the  Done  - elif[ $1=="--del"]; Then  -  forIinch`Echo$2|sed 's/,//g'`; Do  -     if!ID$I &>/dev/NULL; Then  +         Echo "$I NOT EXISTS"  -     Else  +Userdel-R $I A         Echo "Delete $I finished"  at     fi

Test:

Integer test

-le-lt-gt-ge-eq-ne

Character test

= = = > <-n-z

File test

-e-f-d-r-w-x

Combination test conditions

-A: With relation

-O: or relationship

! : Non-relational

If [$#-gt 1-a $#-le 3]

If [$#-gt 1] && [$#-le 3]

Linux--shell Programming (vi) using scripting options and combination condition testing