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2024/12/22 14:21:02 来源:https://blog.csdn.net/m0_65152767/article/details/144222236  浏览:    关键词:莱芜网站seo_商标设计理念_网上如何推广产品_西安网站seo费用
莱芜网站seo_商标设计理念_网上如何推广产品_西安网站seo费用

文章目录

      • 1. Shell 通配符展开(Glob Expansion)
      • 2. 有引号时的行为(推荐)
      • 3. 无引号时的行为
      • 4. 总结原因
      • 5. 推荐实践

root@iZuf67xiyefycct0a9rdi3Z:~# find / -name *.jar
find: paths must precede expression: o2o.jar
Usage: find [-H] [-L] [-P] [-Olevel] [-D help|tree|search|stat|rates|opt|exec|time] [path...] [expression]
root@iZuf67xiyefycct0a9rdi3Z:~# find / -name '*.jar'
/usr/share/java/gettext.jar
/usr/share/java/libintl.jar
/usr/share/ca-certificates-java/ca-certificates-java.jar
/usr/lib/jvm/java-8-openjdk-amd64/lib/tools.jar
/usr/lib/jvm/java-8-openjdk-amd64/lib/sa-jdi.jar
/usr/lib/jvm/java-8-openjdk-amd64/lib/jconsole.jar
/usr/lib/jvm/java-8-openjdk-amd64/lib/dt.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/charsets.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/icedtea-sound.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/zipfs.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/sunec.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/sunpkcs11.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/nashorn.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/jaccess.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/sunjce_provider.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/localedata.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/cldrdata.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/ext/dnsns.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/jce.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/jsse.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/resources.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/management-agent.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/rt.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/security/policy/unlimited/US_export_policy.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/security/policy/unlimited/local_policy.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/security/policy/limited/US_export_policy.jar
/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/security/policy/limited/local_policy.jar
/root/o2o.jar
/root/api-0.0.1-SNAPSHOT.jar
/root/backups/api-0.0.1-SNAPSHOT-2005121808.jar
/root/backups/api-0.0.1-SNAPSHOT-2011111456.jar
/root/backups/o2o-2110271358.jar
/root/backups/api-0.0.1-SNAPSHOT-2003171037.jar
/root/backups/o2o-2207041636.jar
/root/backups/o2o-2106231520.jar
/root/backups/api-0.0.1-SNAPSHOT-2003131851.jar
/root/backups/o2o-2107051533.jar
/root/backups/o2o-2110271357.jar
/root/backups/api-0.0.1-SNAPSHOT-1912101123.jar
/root/backups/o2o-2106211559.jar
/root/backups/o2o-2106110854.jar
/root/backups/api-0.0.1-SNAPSHOT-2011111449.jar
/root/backups/api-0.0.1-SNAPSHOT-2009300856.jar
/root/backups/o2o-2109261013.jar
/root/backups/o2o-2101211406.jar
/root/backups/api-0.0.1-SNAPSHOT-1912161556.jar
/root/backups/api-0.0.1-SNAPSHOT-1911211056.jar
/root/backups/api-0.0.1-SNAPSHOT-1910311824.jar
/root/backups/o2o-2203071836.jar
/root/backups/api-0.0.1-SNAPSHOT-1910151722.jar
/root/backups/api-0.0.1-SNAPSHOT-1910141812.jar
/root/backups/api-0.0.1-SNAPSHOT-1910221142.jar
/root/backups/api-0.0.1-SNAPSHOT-2003251833.jar
/root/backups/api-0.0.1-SNAPSHOT-2003171241.jar
/root/backups/api-0.0.1-SNAPSHOT-1912271913.jar
/root/backups/o2o-2101261347.jar
/root/backups/api-0.0.1-SNAPSHOT-2003180826.jar
/root/backups/api-0.0.1-SNAPSHOT-1910141712.jar
/root/backups/api-0.0.1-SNAPSHOT-1910141735.jar
/root/backups/api-0.0.1-SNAPSHOT-2005131541.jar
/root/backups/o2o-2207071007.jar
/root/backups/o2o-2108121055.jar
/root/backups/api-0.0.1-SNAPSHOT-1910141717.jar
/root/backups/api-0.0.1-SNAPSHOT-2009300858.jar
/root/backups/o2o-2207041512.jar
/root/backups/api-0.0.1-SNAPSHOT-2003261317.jar
/root/backups/o2o-2309180346.jar
/root/backups/api-0.0.1-SNAPSHOT-2011111457.jar
/root/backups/api-0.0.1-SNAPSHOT-1910151715.jar
/root/backups/o2o-2101211432.jar
/root/backups/api-0.0.1-SNAPSHOT-2005131727.jar
/root/backups/api-0.0.1-SNAPSHOT-2006131922.jar
/root/backups/api-0.0.1-SNAPSHOT-1911221029.jar
/root/backups/api-0.0.1-SNAPSHOT-2003250858.jar
/root/backups/api-0.0.1-SNAPSHOT-2008181644.jar
/root/backups/o2o-2209211031.jar
/root/backups/api-0.0.1-SNAPSHOT-2005131540.jar
/root/backups/api-0.0.1-SNAPSHOT-1912271919.jar
/root/backups/api-0.0.1-SNAPSHOT-1912271629.jar
/root/backups/api-0.0.1-SNAPSHOT-1912040956.jar
/root/backups/o2o-2107061034.jar
/root/backups/o2o-2107271720.jar
/root/backups/api-0.0.1-SNAPSHOT-1912041413.jar
/root/backups/api-0.0.1-SNAPSHOT-1911201606.jar
/root/backups/api-0.0.1-SNAPSHOT-1912101143.jar
/root/backups/api-0.0.1-SNAPSHOT-1910141807.jar
/root/backups/o2o-2206161029.jar
/root/backups/o2o-2106211550.jar
/root/backups/api-0.0.1-SNAPSHOT-2002251723.jar
/root/backups/api-0.0.1-SNAPSHOT-2011121414.jar
/root/backups/api-0.0.1-SNAPSHOT-1911042213.jar
/root/backups/o2o-2111261253.jar
/root/backups/api-0.0.1-SNAPSHOT-1910221128.jar
/root/backups/api-0.0.1-SNAPSHOT-1910141914.jar
/root/backups/api-0.0.1-SNAPSHOT-1912300926.jar
/root/backups/api-0.0.1-SNAPSHOT-2003300911.jar
/root/backups/api-0.0.1-SNAPSHOT-1910151132.jar
/root/backups/api-0.0.1-SNAPSHOT-2005131556.jar
/root/backups/api-0.0.1-SNAPSHOT-1912271859.jar
/root/backups/api-0.0.1-SNAPSHOT-2005131609.jar
/root/backups/api-0.0.1-SNAPSHOT-1910151058.jar
/root/backups/api-0.0.1-SNAPSHOT-2003251742.jar
/root/backups/api-0.0.1-SNAPSHOT-1910141937.jar
/root/backups/api-0.0.1-SNAPSHOT-1910141821.jar
/root/backups/api-0.0.1-SNAPSHOT-1912040939.jar
/root/backups/api-0.0.1-SNAPSHOT-2004071550.jar
/root/backups/api-0.0.1-SNAPSHOT-2005131615.jar
/root/backups/api-0.0.1-SNAPSHOT-1912161610.jar
/root/backups/api-0.0.1-SNAPSHOT-1912271720.jar
/root/backups/o2o-2207051114.jar
/root/backups/api-0.0.1-SNAPSHOT-1912101122.jar
/root/backups/api-0.0.1-SNAPSHOT-2003251728.jar
/root/backups/api-0.0.1-SNAPSHOT-2005131754.jar
/root/backups/o2o-2107151440.jar
/root/backups/api-0.0.1-SNAPSHOT-1912040948.jar
/root/backups/api-0.0.1-SNAPSHOT-2003171027.jar
/root/backups/api-0.0.1-SNAPSHOT-1910211009.jar
/root/backups/api-0.0.1-SNAPSHOT-1912161611.jar

在使用 find / -name '*.jar' 时,是否需要加引号取决于 shell 的通配符展开行为。让我们详细分析一下为什么有时需要加引号,有时不需要:

1. Shell 通配符展开(Glob Expansion)

  • 在执行 find 命令之前,shell 会先处理命令行中的通配符(如 *?)。
  • 如果当前目录下存在与 *.jar 匹配的文件,shell 会将 *.jar 展开为匹配的文件列表(如 file1.jar file2.jar),然后传递给 find 命令。
  • 如果没有匹配文件,shell 会将 *.jar 原样传递给 find

2. 有引号时的行为(推荐)

  • 命令:find / -name '*.jar'
  • 效果:引号阻止了 shell 对 *.jar 进行通配符展开,find 接收到的参数就是 *.jar,并按预期查找所有 .jar 文件。
  • 推荐原因:无论当前目录是否存在匹配的文件,find 都会搜索文件名匹配 *.jar 的文件,行为更稳定。

3. 无引号时的行为

  • 命令:find / -name *.jar
  • 效果
    • 如果当前目录有匹配的文件(如 file1.jarfile2.jar),shell 会将 *.jar 展开为 file1.jar file2.jar,变成:
      find / -name file1.jar file2.jar
      
      此时 find 可能会报错或只查找第一个文件。
    • 如果当前目录没有匹配的文件*.jar 原样传递给 find,效果等同于加引号,正常执行。

4. 总结原因

  • 不加引号时:依赖于当前目录是否有匹配的文件:
    • 有匹配文件时,shell 展开,行为可能不符合预期。
    • 无匹配文件时,find 正常执行。
  • 加引号时:始终按预期查找 *.jar 文件,不受当前目录影响。

5. 推荐实践

始终给通配符加引号,例如:

find / -name '*.jar'

这样可以避免 shell 提前展开通配符,确保 find 按预期运行。

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