用于检查特定条件的字符串的 Shell 脚本

在这里，我们将编写一个 shell 脚本，如果接受的字符串不满足特定条件，它将回显（打印）一条合适的消息。假设我们给出了一些特定条件，那么我们的任务是在接受的字符串与条件不匹配时打印消息。

示例 1：

如果接受的字符串长度小于 10，我们将显示一条消息“字符串太短”。

Input:  "abcdef"
Output:  String is too short
Length is 6, which is smaller than 10.

方法：

我们将从用户那里获取一个字符串
我们必须找到字符串的长度，以便我们可以决定它是小于还是大于 10。
我们将使用以下命令找到长度：

len=`echo -n $str | wc -c`

下面是实现：

# Shell script to print message 
# when condition doesn't matched

# taking user input
echo "Enter the String : "
read string

# Finding the length of string 
# -n flag to avoid new line
# wc -c count the chars in a file
len=`echo -n $string | wc -c`

# Checking if length is smaller
# than 10 or not
if [ $len -lt 10 ]
    then
        # if length is smaller 
        # print this message
        echo "String is too short."
fi

输出：

示例 2：我们将接受两个输入字符串并查找两者是否相等。

String1 -> a = “abc”

String2 -> b = “abc”

Here a and b are equal.

编程需要懂一点英语

下面是实现：

# Shell script to check whether two 
# input strings is equal

# take user input
echo "Enter string a : "
read a

echo "Enter string b : "
read b

# check equality of input
if [ "$a" = "$b" ]; then

    # if equal print equal
    echo "Strings are equal."
else
      # if not equal
    echo "Strings are not equal."
fi

输出：

Geeks
Geeks
Strings are equal.

示例 3：

我们正在处理字符串，所以现在我们将把两个字符串作为输入，并检查这两个字符串中哪一个在词典（字母）顺序方面更大。

string1 > string2 : The greater than operator returns true if the left operand is greater than the right sorted by lexicographical (alphabetical) order.

string1 < string2 : The less than operator returns true if the right operand is greater than the right sorted by lexicographical (alphabetical) order.

编程需要懂一点英语

# Shell script to check which 
# string is lexicographiclly
# larger

# user input
echo "Enter String a : "
read a

echo "Enter String b : "
read b

# if a is greater than b
if [[ "$a" > "$b" ]]; then
    echo "${a} is lexicographically greater then ${b}."

# if b is greater than a
elif [[ "$a" < "$b" ]]; then
    echo "${b} is lexicographically greater than ${a}."

# if both are equal
else
    echo "Strings are equal"
fi

输出：

abc
def
def is lexicographically greater than abc.