100个shell脚本。每天一个坚持下去。
20180306一、case
#!/bin/bash
#测试case
echo "Hit a key,then hit return."
read keypress
#开始case
case "$keypress" in
[[:lower:]])
echo "lowercase letter.";;
[[:upper:]])
echo "uppercase letter.";;
)
echo "digit.";;
*)
echo "other letter";;
esac
##收到不同参数，输出不同结果。
20180307
二、
#!/bin/bash
result=expr 2 - 100
echo "$result"
result=$((5+5))
echo $result
result=$
echo $result
###数值运算
20180308
三、
#!/bin/bash
for var in 1 2 3 4 5 6 7 8 9
do
echo "then is number is $var"
done
for var in {1..8}
do
echo"then is number is $var"
done
~
20180309
四、
#!/bin/bash
sum=0;
for i in {0..100..2}
do
let "sum+=i"
done
echo "then sum is $sum"
~
20180310
五、
#!/bin/bash
for file in $(ls)
do
echo $file
done
20180311
六、
#!/bin/bash
for ((i=1;i /dev/null
let "i++"
done
20180313
九、
#!/bin/bash
i=1
until [ "$i" -eq 21 ]
do
userdel -r user$i
let "i++"
done
十、0314
#!/bin/bash
echo'是否是非空'
a='abc'
test $a
echo $?
echo'是否非空'
test -n $a
echo $?
echo '是否是空'
test -z $a
echo $?
echo'是否字符串对比'
b='abc'
test $a = $b
echo $?
echo'是否不等'
test $a != $b
echo $?
[ $a = $b ]
echo $?
[ $a != $b ]
echo $?
echo '是否等于'
[ 2 -eq 3 ]
echo $?
echo'是否不等于'
[ 3 -ne 2 ]
echo $?
echo'是否大于'
[ 10 -gt 9 ]
echo $?
echo'是否小于'
[ 8 -lt 9]
echo $?
echo '是否大于等于'
[ 10 -ge 10 ]
echo $?
echo'是否小于等于'
[ 10 -le 10 ]
echo $?
echo'文件是否存在'
[ -a 13.sh ]
echo $?
echo'是否是块文件'
[ -b /etc/rc.local ]
echo $?
echo'是否是字符文件'
[ -c1.sh ]
echo $?
echo '是否存在且是目录'
[ -d /etc/cron.d ]
echo $?
echo '是否为空文件'
[ -s /etc/rc.d/rc.local ]
echo $?
echo '是否是连接文件'
[ -L 10.sh ]
echo $?
echo '是否设置SUID位'
[ -u 12.sh ]
echo $?
echo '判断逻辑非与或'
a=30
test"$a"-gt 20 -a "$a" -lt 100
echo $?
十四、0315（if语句）
#!/bin/bash
echo "学生考试分数"
read num
if [ -z "$num" ]; then
echo "请输入一个分数:"
read num
else
if [ "$num" -lt 0 -o "$num" -gt 100 ]; then
echo "请输入0-100:"
read num
else
if [ "$num" -ge 90 ]; then
echo "成绩A"
else
if [ "$num" -ge 80 ]; then
echo "成绩B"
else
if[ "$num" -ge 70 ]; then
echo "成绩C"
else
if [ "$num" -ge 60 ];then
echo "成绩D"
else
if [ "$num" -lt 60 ]; then
echo "不及格"
fi
fi
fi
fi
fi
fi
fi
####>>>>>>>>if多分支语句
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