我在Bash中有一个字符串:

string="My string"

如何测试它是否包含另一个字符串?

if [ $string ?? 'foo' ]; then
  echo "It's there!"
fi

哪里是我不认识的接线员。我使用echo和grep吗?

if echo "$string" | grep 'foo'; then
  echo "It's there!"
fi

这看起来有点笨拙。


当前回答

如果您喜欢正则表达式方法:

string='My string';

if [[ $string =~ "My" ]]; then
   echo "It's there!"
fi

其他回答

试试oobash。

它是Bash 4的OO风格字符串库。它支持德语元音变音。它是用巴什语写的。

有许多函数可用:-base64Decode、-base64Encode、-acapital、-center、-charAt、concat、-concontains、-count、-endsWith、-equals、-equalsIgnoreCase、-reverse、-hashCode、-indexOf、-isAlnum、-isAlpha、-isAscii、-isDigit、-isEmpty、-isHexDigit、-isLowerCase、-isSpace、-isPrintable、-isUpperCase、-isVisible、-lastIndexOf、-length、-matches、-replaceAll、-replaceFirst、-startsWith,-substring、-swapCase、-toLowerCase、-toString、-toUpperCase、-trim和-zfill。

查看包含的示例:

[Desktop]$ String a testXccc
[Desktop]$ a.contains tX
true
[Desktop]$ a.contains XtX
false

oobash可在Sourceforge.net上获得。

这里回答的问题的扩展如何判断POSIX sh中的字符串是否包含另一个字符串?:

此解决方案适用于特殊字符:

# contains(string, substring)
#
# Returns 0 if the specified string contains the specified substring,
# otherwise returns 1.
contains() {
    string="$1"
    substring="$2"

    if echo "$string" | $(type -p ggrep grep | head -1) -F -- "$substring" >/dev/null; then
        return 0    # $substring is in $string
    else
        return 1    # $substring is not in $string
    fi
}

contains "abcd" "e" || echo "abcd does not contain e"
contains "abcd" "ab" && echo "abcd contains ab"
contains "abcd" "bc" && echo "abcd contains bc"
contains "abcd" "cd" && echo "abcd contains cd"
contains "abcd" "abcd" && echo "abcd contains abcd"
contains "" "" && echo "empty string contains empty string"
contains "a" "" && echo "a contains empty string"
contains "" "a" || echo "empty string does not contain a"
contains "abcd efgh" "cd ef" && echo "abcd efgh contains cd ef"
contains "abcd efgh" " " && echo "abcd efgh contains a space"

contains "abcd [efg] hij" "[efg]" && echo "abcd [efg] hij contains [efg]"
contains "abcd [efg] hij" "[effg]" || echo "abcd [efg] hij does not contain [effg]"

contains "abcd *efg* hij" "*efg*" && echo "abcd *efg* hij contains *efg*"
contains "abcd *efg* hij" "d *efg* h" && echo "abcd *efg* hij contains d *efg* h"
contains "abcd *efg* hij" "*effg*" || echo "abcd *efg* hij does not contain *effg*"

我的.bash_profile文件以及我如何使用grep:

如果PATH环境变量包含我的两个bin目录,请不要追加它们,

# .bash_profile
# Get the aliases and functions
if [ -f ~/.bashrc ]; then
    . ~/.bashrc
fi

U=~/.local.bin:~/bin

if ! echo "$PATH" | grep -q "home"; then
    export PATH=$PATH:${U}
fi

使用jq:

string='My long string'
echo $string | jq -Rr 'select(contains("long"))|"It is there"'

jq中最困难的事情是打印单个引用:

echo $string | jq --arg quote "'" -Rr 'select(contains("long"))|"It\($quote)s there"'

仅使用jq检查条件:

if jq -Re 'select(contains("long"))|halt' <<< $string; then
    echo "It's there!"
fi

Bash 4+示例。注意:当单词包含空格等时,不使用引号会导致问题。请始终在Bash、IMO中引用。

以下是一些Bash 4+示例:

示例1,检查字符串中的“yes”(不区分大小写):

    if [[ "${str,,}" == *"yes"* ]] ;then

示例2,检查字符串中的“yes”(不区分大小写):

    if [[ "$(echo "$str" | tr '[:upper:]' '[:lower:]')" == *"yes"* ]] ;then

示例3,检查字符串中的“yes”(区分大小写):

     if [[ "${str}" == *"yes"* ]] ;then

示例4,检查字符串中的“yes”(区分大小写):

     if [[ "${str}" =~ "yes" ]] ;then

示例5,完全匹配(区分大小写):

     if [[ "${str}" == "yes" ]] ;then

示例6,完全匹配(不区分大小写):

     if [[ "${str,,}" == "yes" ]] ;then

示例7,完全匹配:

     if [ "$a" = "$b" ] ;then

示例8,通配符match.ext(不区分大小写):

     if echo "$a" | egrep -iq "\.(mp[3-4]|txt|css|jpg|png)" ; then

示例9,对区分大小写的字符串使用grep:

     if echo "SomeString" | grep -q "String"; then

示例10,对不区分大小写的字符串使用grep:

     if echo "SomeString" | grep -iq "string"; then

示例11,对字符串使用grep,不区分大小写,带通配符:

     if echo "SomeString" | grep -iq "Some.*ing"; then

示例12,使用doublehash进行比较(如果变量为空会导致假阳性等)(区分大小写):

     if [[ ! ${str##*$substr*} ]] ;then  #found

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