{"id":147,"date":"2021-12-13T19:54:16","date_gmt":"2021-12-13T11:54:16","guid":{"rendered":"http:\/\/139.9.1.231\/?p=147"},"modified":"2021-12-13T19:54:16","modified_gmt":"2021-12-13T11:54:16","slug":"shell","status":"publish","type":"post","link":"http:\/\/139.9.1.231\/index.php\/2021\/12\/13\/shell\/","title":{"rendered":"shell"},"content":{"rendered":"\n

\u4e32\u884c\u6267\u884c\u7a0b\u5e8f && ||<\/h3>\n\n\n\n
  1. command1 ; commond2 \u6267\u884c\u5b8c1\u5728\u6267\u884c2<\/li>
  2. commond1 && commond2 \u5982\u679ccmd1\u6267\u884c\u6210\u529f\uff08$?=0\uff09,\u5219\u5f00\u59cb\u6267\u884ccmd2\uff0c\u5982\u679ccmd1\u6267\u884c\u9519\u8bef\uff08$?=1\uff09,\u5219\u4e0d\u6267\u884ccmd2<\/li>
  3. cmd1 || cmd2 \u5982\u679ccmd1\u6267\u884c\u9519\u8bef\uff08$?=1\uff09\uff0c\u624d\u6267\u884ccmd2 \uff0c\u5426\u5219\u4e0d\u6267\u884ccmd2<\/li><\/ol>\n\n\n\n

    test\u547d\u4ee4<\/h3>\n\n\n\n

    \u572811.15\u8bfe\u7a0b\u603b\u7ed3\u90e8\u5206\u5df2\u7ecf\u7ed9\u51fa\uff0c\u8fd9\u91cc\u5c31\u4e0d\u518d\u8d58\u8ff0\u3002<\/p>\n\n\n\n

    exit()\u547d\u4ee4<\/h3>\n\n\n\n
    exit \u9000\u51fa\u5f53\u524dshell\nLinux exit\u547d\u4ee4\u7528\u4e8e\u9000\u51fa\u76ee\u524d\u7684shell\u3002\n\u6267\u884cexit\u53ef\u4f7fshell\u4ee5\u6307\u5b9a\u7684\u72b6\u6001\u503c\u9000\u51fa\u3002\u82e5\u4e0d\u8bbe\u7f6e\u72b6\u6001\u503c\u53c2\u6570\uff0c\u5219shell\u4ee5\u9884\u8bbe\u503c\u9000\u51fa\u3002\u72b6\u6001\u503c0\u4ee3\u8868\u6267\u884c\u6210\u529f\uff0c\u5176\u4ed6\u503c\u4ee3\u8868\u6267\u884c\u5931\u8d25\u3002exit\u4e5f\u53ef\u7528\u5728script\uff0c\u79bb\u5f00\u6b63\u5728\u6267\u884c\u7684script\uff0c\u56de\u5230shell\u3002\n0    \u6267\u884c\u6210\u529f\n1    \u6267\u884c\u5931\u8d25\n$?    \u53c2\u7167\u4e0a\u4e00\u4e2a\u72b6\u6001\u503c<\/code><\/pre>\n\n\n\n
    linux\u811a\u672c\uff1a if\u8bed\u53e5<\/h3>\n\n\n\n
    if [expression] then;\n    comd\nelif [expression] then ;\n    commd\nelse \n    commd\nfi\nif\u548cthen\u5199\u5728\u540c\u4e00\u884c\u65f6\uff0c\u9700\u8981\u5206\u53f7\u5206\u9694\u3002\u5206\u53f7\u662f Bash \u7684\u547d\u4ee4\u5206\u9694\u7b26\u3002\u5b83\u4eec\u4e5f\u53ef\u4ee5\u5199\u6210\u4e24\u884c\uff0c\u8fd9\u65f6\u4e0d\u9700\u8981\u5206\u53f7\u3002\n\nBash \u8fd8\u63d0\u4f9b\u4e86((...))\u4f5c\u4e3a\u7b97\u672f\u6761\u4ef6\uff0c\u8fdb\u884c\u7b97\u672f\u8fd0\u7b97\u7684\u5224\u65ad\u3002\n\nif ((3 > 2)); then\n  echo \"true\"\nfi<\/code><\/pre>\n\n\n\n
    case\u7ed3\u6784<\/h3>\n\n\n\n
    case\u7ed3\u6784\u7528\u4e8e\u591a\u503c\u5224\u65ad\uff0c\u53ef\u4ee5\u4e3a\u6bcf\u4e2a\u503c\u6307\u5b9a\u5bf9\u5e94\u7684\u547d\u4ee4\uff0c\u8ddf\u5305\u542b\u591a\u4e2aelif\u7684if\u7ed3\u6784\u7b49\u4ef7\uff0c\u4f46\u662f\u8bed\u4e49\u66f4\u597d\u3002\u5b83\u7684\u8bed\u6cd5\u5982\u4e0b\u3002<\/p>\n\n\n\n
    case expression in\n  pattern1 )\n    commands ;;\n  pattern2 )\n    commands ;;\n  pattern3 )\n    commands ;;\n  *) \n    commands ;;\n\u6700\u540e\u4e00\u6761\u5339\u914d\u8bed\u53e5\u7684\u6a21\u5f0f\u662f*\uff0c\u8fd9\u4e2a\u901a\u914d\u7b26\u53ef\u4ee5\u5339\u914d\u5176\u4ed6\u5b57\u7b26\u548c\u6ca1\u6709\u8f93\u5165\u5b57\u7b26\u7684\u60c5\u51b5\uff0c\u7c7b\u4f3cif\u7684else\u90e8\u5206\n  ...\nesac<\/code><\/pre>\n\n\n\n
    \u4f8b\u5b50\uff1a<\/p>\n\n\n\n
    echo -n \"\u8f93\u5165\u4e00\u4e2a1\u52303\u4e4b\u95f4\u7684\u6570\u5b57\uff08\u5305\u542b\u4e24\u7aef\uff09> \"\nread character\ncase $character in\n  1 ) echo 1\n    ;;\n  2 ) echo 2\n    ;;\n  3 ) echo 3\n    ;;\n  * ) echo \u8f93\u5165\u4e0d\u7b26\u5408\u8981\u6c42\nesac<\/code><\/pre>\n\n\n\n
    while \u5faa\u73af<\/h3>\n\n\n\n
    while\u5faa\u73af\u6709\u4e00\u4e2a\u5224\u65ad\u6761\u4ef6\uff0c\u53ea\u8981\u7b26\u5408\u6761\u4ef6\uff0c\u5c31\u4e0d\u65ad\u5faa\u73af\u6267\u884c\u6307\u5b9a\u7684\u8bed\u53e5\u3002<\/p>\n\n\n\n
    while condition; do\n  commands\ndone<\/code><\/pre>\n\n\n\n
    \u4e0a\u9762\u4ee3\u7801\u4e2d\uff0c\u53ea\u8981\u6ee1\u8db3\u6761\u4ef6condition\uff0c\u5c31\u4f1a\u6267\u884c\u547d\u4ee4commands\u3002\u7136\u540e\uff0c\u518d\u6b21\u5224\u65ad\u662f\u5426\u6ee1\u8db3\u6761\u4ef6condition\uff0c\u53ea\u8981\u6ee1\u8db3\uff0c\u5c31\u4f1a\u4e00\u76f4\u6267\u884c\u4e0b\u53bb\u3002\u53ea\u6709\u4e0d\u6ee1\u8db3\u6761\u4ef6\uff0c\u624d\u4f1a\u9000\u51fa\u5faa\u73af\u3002
    \n\u5faa\u73af\u6761\u4ef6condition\u53ef\u4ee5\u4f7f\u7528test\u547d\u4ee4\uff0c\u8ddfif\u7ed3\u6784\u7684\u5224\u65ad\u6761\u4ef6\u5199\u6cd5\u4e00\u81f4\u3002<\/p>\n\n\n\n
    while true\ndo\n  echo 'Hi, while looping ...';\ndone<\/code><\/pre>\n\n\n\n
    for \u5faa\u73af<\/h3>\n\n\n\n
    for\u2026in \u5faa\u73af
    \nfor\u2026in\u5faa\u73af\u7528\u4e8e\u904d\u5386\u5217\u8868\u7684\u6bcf\u4e00\u9879\u3002<\/p>\n\n\n\n
    for variable in list\ndo\n  commands\ndone<\/code><\/pre>\n\n\n\n
    \u4e0a\u9762\u8bed\u6cd5\u4e2d\uff0cfor\u5faa\u73af\u4f1a\u4f9d\u6b21\u4ecelist\u5217\u8868\u4e2d\u53d6\u51fa\u4e00\u9879\uff0c\u4f5c\u4e3a\u53d8\u91cfvariable\uff0c\u7136\u540e\u5728\u5faa\u73af\u4f53\u4e2d\u8fdb\u884c\u5904\u7406\u3002<\/p>\n\n\n\n
    \u5173\u952e\u8bcddo\u53ef\u4ee5\u8ddffor\u5199\u5728\u540c\u4e00\u884c\uff0c\u4e24\u8005\u4f7f\u7528\u5206\u53f7\u5206\u9694\u3002<\/p>\n\n\n\n
    for i in word1 word2 word3; do\n  echo $i\ndone<\/code><\/pre>\n\n\n\n
    for\u5faa\u73af\u8fd8\u652f\u6301 C \u8bed\u8a00\u7684\u5faa\u73af\u8bed\u6cd5\u3002<\/p>\n\n\n\n
    for (( expression1; expression2; expression3 )); do\n  commands\ndone<\/code><\/pre>\n\n\n\n
    break\uff0ccontinue<\/h3>\n\n\n\n
    Bash \u63d0\u4f9b\u4e86\u4e24\u4e2a\u5185\u90e8\u547d\u4ee4break\u548ccontinue\uff0c\u7528\u6765\u5728\u5faa\u73af\u5185\u90e8\u8df3\u51fa\u5faa\u73af\u3002
    \nbreak\u547d\u4ee4\u7acb\u5373\u7ec8\u6b62\u5faa\u73af\uff0c\u7a0b\u5e8f\u7ee7\u7eed\u6267\u884c\u5faa\u73af\u5757\u4e4b\u540e\u7684\u8bed\u53e5\uff0c\u5373\u4e0d\u518d\u6267\u884c\u5269\u4e0b\u7684\u5faa\u73af\u3002<\/p>\n\n\n\n
    select \u7ed3\u6784<\/h3>\n\n\n\n
    select\u7ed3\u6784\u4e3b\u8981\u7528\u6765\u751f\u6210\u7b80\u5355\u7684\u83dc\u5355\u3002\u5b83\u7684\u8bed\u6cd5\u4e0efor\u2026in\u5faa\u73af\u57fa\u672c\u4e00\u81f4\u3002<\/p>\n\n\n\n
    select name\n<\/code><\/pre>\n\n\n
    [in list]<\/p>\n\n\n\n
    \ndo\n  commands\ndone\n<\/p>\n\n\n\n
    Bash \u4f1a\u5bf9select\u4f9d\u6b21\u8fdb\u884c\u4e0b\u9762\u7684\u5904\u7406\u3002
    \nselect\u751f\u6210\u4e00\u4e2a\u83dc\u5355\uff0c\u5185\u5bb9\u662f\u5217\u8868list\u7684\u6bcf\u4e00\u9879\uff0c\u5e76\u4e14\u6bcf\u4e00\u9879\u524d\u9762\u8fd8\u6709\u4e00\u4e2a\u6570\u5b57\u7f16\u53f7\u3002
    \nBash \u63d0\u793a\u7528\u6237\u9009\u62e9\u4e00\u9879\uff0c\u8f93\u5165\u5b83\u7684\u7f16\u53f7\u3002
    \n\u7528\u6237\u8f93\u5165\u4ee5\u540e\uff0cBash \u4f1a\u5c06\u8be5\u9879\u7684\u5185\u5bb9\u5b58\u5728\u53d8\u91cfname\uff0c\u8be5\u9879\u7684\u7f16\u53f7\u5b58\u5165\u73af\u5883\u53d8\u91cfREPLY\u3002\u5982\u679c\u7528\u6237\u6ca1\u6709\u8f93\u5165\uff0c\u5c31\u6309\u56de\u8f66\u952e\uff0cBash \u4f1a\u91cd\u65b0\u8f93\u51fa\u83dc\u5355\uff0c\u8ba9\u7528\u6237\u9009\u62e9\u3002
    \n\u6267\u884c\u547d\u4ee4\u4f53commands\u3002
    \n\u6267\u884c\u7ed3\u675f\u540e\uff0c\u56de\u5230\u7b2c\u4e00\u6b65\uff0c\u91cd\u590d\u8fd9\u4e2a\u8fc7\u7a0b\u3002<\/p>\n\n\n\n
    let \u547d\u4ee4<\/h3>\n\n\n\n
    let\u547d\u4ee4\u58f0\u660e\u53d8\u91cf\u65f6\uff0c\u53ef\u4ee5\u76f4\u63a5\u6267\u884c\u7b97\u672f\u8868\u8fbe\u5f0f\u3002<\/p>\n\n\n\n
    $ let foo=1+2\n$ echo $foo\n3<\/code><\/pre>\n\n\n\n
    \u4e0a\u9762\u4f8b\u5b50\u4e2d\uff0clet\u547d\u4ee4\u53ef\u4ee5\u76f4\u63a5\u8ba1\u7b971 + 2\u3002<\/p>\n\n\n\n
    let\u547d\u4ee4\u7684\u53c2\u6570\u8868\u8fbe\u5f0f\u5982\u679c\u5305\u542b\u7a7a\u683c\uff0c\u5c31\u9700\u8981\u4f7f\u7528\u5f15\u53f7\u3002<\/p>\n\n\n\n
    $ let \"foo = 1 + 2\"<\/code><\/pre>\n\n\n\n
    let\u53ef\u4ee5\u540c\u65f6\u5bf9\u591a\u4e2a\u53d8\u91cf\u8d4b\u503c\uff0c\u8d4b\u503c\u8868\u8fbe\u5f0f\u4e4b\u95f4\u4f7f\u7528\u7a7a\u683c\u5206\u9694\u3002<\/p>\n\n\n\n
    $ let \"v1 = 1\" \"v2 = v1++\"\n$ echo $v1,$v2\n2,1<\/code><\/pre>\n\n\n\n
    \u4e0a\u9762\u4f8b\u5b50\u4e2d\uff0clet\u58f0\u660e\u4e86\u4e24\u4e2a\u53d8\u91cfv1\u548cv2\uff0c\u5176\u4e2dv2\u7b49\u4e8ev1++\uff0c\u8868\u793a\u5148\u8fd4\u56dev1\u7684\u503c\uff0c\u7136\u540ev1\u81ea\u589e\u3002<\/p>\n\n\n\n
    expr \u8ba1\u7b97\u5668<\/h3>\n\n\n\n
    expr\u547d\u4ee4\u662f\u4e00\u4e2a\u624b\u5de5\u547d\u4ee4\u884c\u8ba1\u6570\u5668\uff0c\u7528\u4e8e\u5728UNIX\/LINUX\u4e0b\u6c42\u8868\u8fbe\u5f0f\u53d8\u91cf\u7684\u503c\uff0c\u4e00\u822c\u7528\u4e8e\u6574\u6570\u503c\uff0c\u4e5f\u53ef\u7528\u4e8e\u5b57\u7b26\u4e32\u3002<\/p>\n\n\n\n
    expr \u8868\u8fbe\u5f0f
    \n\u8868\u8fbe\u5f0f\u8bf4\u660e:<\/p>\n\n\n\n
    \u7528\u7a7a\u683c\u9694\u5f00\u6bcf\u4e2a\u9879\uff1b\n\u7528\u53cd\u659c\u6760 \\ \u653e\u5728 shell \u7279\u5b9a\u7684\u5b57\u7b26\u524d\u9762\uff1b \"\\*\"\n\u5bf9\u5305\u542b\u7a7a\u683c\u548c\u5176\u4ed6\u7279\u6b8a\u5b57\u7b26\u7684\u5b57\u7b26\u4e32\u8981\u7528\u5f15\u53f7\u62ec\u8d77\u6765<\/code><\/pre>\n\n\n\n
     > expr 14 % 9\n 5\n > expr 10 + 10\n 20\n > expr 1000 + 900\n 1900\n > expr 30 \/ 3 \/ 2\n 5\n > expr 30 \\* 3 (\u4f7f\u7528\u4e58\u53f7\u65f6\uff0c\u5fc5\u987b\u7528\u53cd\u659c\u7ebf\u5c4f\u853d\u5176\u7279\u5b9a\u542b\u4e49\u3002\u56e0\u4e3ashell\u53ef\u80fd\u4f1a\u8bef\u89e3\u663e\u793a\u661f\u53f7\u7684\u610f\u4e49)\n 90\n > expr 30 * 3\n expr: Syntax error<\/code><\/pre>\n\n\n\n
    $[] \u8ba1\u7b97<\/h3>\n\n\n\n
    Shell $[] \u7684\u7528\u6cd5\u5982\u4e0b\uff1a<\/p>\n\n\n\n
    $[\u8868\u8fbe\u5f0f]\n$[5+3]\n$[] \u4f1a\u5bf9\u8868\u8fbe\u5f0f\u8fdb\u884c\u8ba1\u7b97\uff0c\u5e76\u53d6\u5f97\u8ba1\u7b97\u7ed3\u679c\u3002\u5982\u679c\u8868\u8fbe\u5f0f\u4e2d\u5305\u542b\u4e86\u53d8\u91cf\uff0c\u90a3\u4e48\u4f60\u53ef\u4ee5\u52a0$\uff0c\u4e5f\u53ef\u4ee5\u4e0d\u52a0\u3002<\/code><\/pre>\n\n\n\n
    bc \u547d\u4ee4<\/h3>\n\n\n\n
    bc\u662f\u4efb\u610f\u7cbe\u5ea6\u8ba1\u7b97\u5668\u8bed\u8a00\uff0c\u901a\u5e38\u5728linux\u4e0b\u5f53\u8ba1\u7b97\u5668\u7528\u3002<\/p>\n\n\n\n
    \u5b83\u7c7b\u4f3c\u57fa\u672c\u7684\u8ba1\u7b97\u5668, \u4f7f\u7528\u8fd9\u4e2a\u8ba1\u7b97\u5668\u53ef\u4ee5\u505a\u57fa\u672c\u7684\u6570\u5b66\u8fd0\u7b97\u3002
    \n\u5e38\u7528\u7684\u8fd0\u7b97\uff1a<\/p>\n\n\n\n
    + \u52a0\u6cd5\n- \u51cf\u6cd5\n* \u4e58\u6cd5\n\/ \u9664\u6cd5\n^ \u6307\u6570\n% \u4f59\u6570<\/code><\/pre>\n\n\n\n
    \u5b9e\u4f8b\uff1a\n\u901a\u8fc7\u7ba1\u9053\u7b26\n\n$ echo \"15+5\" | bc\n20\n\n$ echo 'scale=2; (2.777 - 1.4744)\/1' | bc\n1.30\n\n$ echo \"10^10\" | bc \n10000000000\n\n$ echo \"sqrt(100)\" | bc\n10<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
    \u4e32\u884c\u6267\u884c\u7a0b\u5e8f && || command1 ; commond2 \u6267\u884c\u5b8c1\u5728\u6267\u884c2 commo … \u7ee7\u7eed\u9605\u8bfbshell<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[3],"tags":[],"_links":{"self":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/147"}],"collection":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/comments?post=147"}],"version-history":[{"count":1,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/147\/revisions"}],"predecessor-version":[{"id":148,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/posts\/147\/revisions\/148"}],"wp:attachment":[{"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/media?parent=147"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/categories?post=147"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/139.9.1.231\/index.php\/wp-json\/wp\/v2\/tags?post=147"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}