{"id":101,"date":"2013-05-09T20:04:37","date_gmt":"2013-05-09T12:04:37","guid":{"rendered":"http:\/\/coderbee.net\/?p=101"},"modified":"2013-05-09T11:07:43","modified_gmt":"2013-05-09T03:07:43","slug":"shell-%e8%84%9a%e6%9c%ac%e4%b9%8b%e5%8f%98%e9%87%8f%e3%80%81%e6%95%b0%e7%bb%84%e3%80%81%e6%89%a9%e5%b1%95","status":"publish","type":"post","link":"https:\/\/coderbee.net\/index.php\/linux\/20130509\/101","title":{"rendered":"shell \u811a\u672c\u4e4b\u53d8\u91cf\u3001\u6570\u7ec4\u3001\u6269\u5c55"},"content":{"rendered":"

\u53d8\u91cf<\/h2>\n

\u53d8\u91cf\u662f\u4ec0\u4e48<\/h3>\n

\u5728Bash shell\u4e2d\uff0c\u53ea\u6709\u4e00\u79cd\u6570\u636e\u578b\u6001\uff1a\u4ee5\u5b57\u7b26\u7ec4\u6210\u7684\u5b57\u7b26\u4e32\u3002Bash Shell\u628a\u4efb\u4f55\u5b58\u50a8\u5728\u53d8\u91cf\u4e2d\u7684\u503c\uff0c\u7686\u89c6\u4e3a\u4ee5\u5b57\u7b26\u7ec4\u6210\u7684\u201c\u5b57\u7b26\u4e32\u201d\u3002
\n\u8981\u4f7f\u7528Bash Shell\u53d8\u91cf\uff0c\u4e0d\u9700\u8981\u7ecf\u8fc7\u5b9e\u73b0\u58f0\u660e\u3002<\/p>\n

\u6bcf\u4e2aShell\u73af\u5883\u90fd\u4f1a\u7ef4\u62a4\u4e00\u4efd\u5b83\u4eec\u81ea\u5df1\u7684\u53d8\u91cf\u7a7a\u95f4\uff0c\u5f7c\u6b64\u4e0d\u4e92\u76f8\u5f71\u54cd\u3002<\/p>\n

\u53d8\u91cf\u547d\u540d<\/h3>\n

\u53d8\u91cf\u540d\u53ef\u7528\u82f1\u6587\u5b57\u6bcd\u3001\u6570\u5b57\u53ca\u4e0b\u5212\u7ebf\u7ec4\u6210\uff0c\u4f46\u5f00\u5934\u7b2c\u4e00\u4e2a\u5b57\u7b26\u4e0d\u80fd\u662f\u6570\u5b57\uff1b\u53d8\u91cf\u540d\u957f\u5ea6\u4e0d\u9650\u5236\uff1b\u5927\u5c0f\u5199\u654f\u611f\uff1b<\/p>\n

\u53d8\u91cf\u8d4b\u503c<\/h3>\n

\u7ed9\u53d8\u91cf\u8d4b\u503c\u65f6\uff0c\u7b49\u53f7\u4e24\u8fb9\u4e0d\u53ef\u4ee5\u6709\u7a7a\u767d\uff1b\u82e5\u53d8\u91cf\u503c\u6709\u7a7a\u767d\uff0c\u5219\u8981\u7528\u5f15\u53f7\u62ec\u8d77\u6765\u3002<\/p>\n

\u53d8\u91cf\u548c\u5f15\u53f7<\/h3>\n

\u63a8\u8350\u4e60\u60ef\uff1a\u628a\u5b57\u7b26\u4e32\u7528\u53cc\u5f15\u53f7\u6216\u5355\u5f15\u53f7\u62ec\u8d77\u6765\u3002
\n\u5728\u53cc\u5f15\u53f7\u4e2d\uff0c\u53ef\u8fdb\u884c\u4ee5\u4e0b3\u4e2a\u64cd\u4f5c\uff1a\u66ff\u6362\u53d8\u91cf\uff1b\u66ff\u6362\u547d\u4ee4\u6267\u884c\u7ed3\u679c\uff1b\u66ff\u6362\u7b97\u672f\u8fd0\u7b97\u7ed3\u679c\u3002<\/p>\n

\u5355\u5f15\u53f7\u7684\u4f5c\u7528\u662f\u5f62\u6210\u4e00\u4e2a\u6240\u89c1\u5373\u6240\u5f97\u7684\u5b57\u7b26\u4e32\uff0c\u4e0d\u4f1a\u8fdb\u884c\u4efb\u4f55\u53d8\u91cf\u66ff\u6362\u7684\u64cd\u4f5c\u3002<\/p>\n

\u53d6\u53d8\u91cf\u503c<\/h3>\n

$\u53d8\u91cf\u540d<\/code> \u6216 ${\u53d8\u91cf\u540d}<\/code>
\n\u524d\u8005\u5728\u53d8\u91cf\u540d\u540e\u9762\u662f\u7a7a\u767d\u7b26\u65f6\u4f7f\u7528\uff0c\u540e\u8005\u5728\u53d8\u91cf\u540d\u4e0e\u5176\u4ed6\u5b57\u6bcd\u3001\u6570\u5b57\u3001\u4e0b\u5212\u7ebf\u6df7\u5408\u65f6\u4f7f\u7528\u3002<\/p>\n

\u53d6\u6d88\u53d8\u91cf\uff1a<\/h3>\n

\u53d6\u6d88\u53d8\u91cf\u5c31\u662f\u628a\u53d8\u91cf\u4ece\u53d8\u91cf\u7a7a\u95f4\u5220\u9664\u91ca\u653e\u3002<\/p>\n

\nunset \u53d8\u91cf\u540d\nunset -v \u53d8\u91cf\u540d\nunset -f \u51fd\u6570\u540d\n<\/code><\/pre>\n
\u6e05\u7a7a\u53d8\u91cf<\/h3>\n
\u53d8\u91cf\u4ecd\u7136\u5b58\u5728\uff0c\u53ea\u4e0d\u8fc7\u503c\u662f\u957f\u5ea6\u4e3a0\u7684\u5b57\u7b26\u4e32\u3002<\/p>\n
\u53d8\u91cf\u540d=<\/code><\/p>\n
<\/p>\n
\u73af\u5883\u53d8\u91cf<\/h3>\n
\u7236shell\u8f93\u51fa\u73af\u5883\u53d8\u91cf\u540e\uff0c\u540e\u7eed\u7684\u5404\u79cd\u64cd\u4f5c\u5305\u62ec\u5b50shell\u90fd\u53ef\u63d0\u53d6\u8be5\u53d8\u91cf\u7684\u503c\u3002
\nexport var=\"var value\"<\/code>
\ndeclare -x envVar=\"var value\"<\/code><\/p>\n
bash\u5185\u7f6e\u53d8\u91cf<\/h3>\n
\nCDPATH\uff1a cd\u547d\u4ee4\u7684\u641c\u7d22\u8def\u5f84\uff0c\u81ea\u5b9a\u4e49CDPATH\uff0c\u53ef\u7f29\u77ed\u952e\u5165\u8def\u5f84\u6587\u4ef6\u540d\u7684\u957f\u5ea6\u3002\nIFS\uff1a\u5b9a\u4e49\u5b57\u6bb5\u5206\u9694\u7b26\u3002\u9ed8\u8ba4\u4e3a\uff1a\u7a7a\u683c\u7b26\u3001tab\u5b57\u7b26\u3001\u6362\u884c\u7b26\u3002\nOLDPWD\uff1a\u524d\u4e00\u4e2a\u5de5\u4f5c\u76ee\u5f55\u3002\n\n\n$0\uff1a\u6267\u884c\u7a0b\u5e8f\u7684\u540d\u79f0\u3002\n$1-$n\uff1a\u4f4d\u7f6e\u53c2\u6570\u3002\u4f20\u5165\u7a0b\u5e8f\u6216\u51fd\u6570\u7684\u53c2\u6570\uff0c\u7b2c\u4e00\u4e2a\u662f$1, n\u8d85\u8fc79\u7684\uff0c\u7528${n}\n$*\uff1a\u4ee3\u8868\u6240\u6709\u4f4d\u7f6e\u53c2\u6570\uff0c\u5e76\u4e14\u89c6\u4e3a\u4e00\u4e2a\u5b57\u7b26\u4e32\u3002\n$@\uff1a\u4ee3\u8868\u6240\u6709\u4f4d\u7f6e\u53c2\u6570\uff0c\u4f46$@\u4ee3\u8868\u5404\u4f4d\u7f6e\u53c2\u6570\u7684\u4e32\u884c\u3002\n$#\uff1a\u4f4d\u7f6e\u53c2\u6570\u7684\u4e2a\u6570\u3002\n$-\uff1abash shell\u76ee\u524d\u4f7f\u7528\u7684\u529f\u80fd\u9009\u9879\u3002\n$?\uff1a\u4e0a\u4e00\u4e2a\u547d\u4ee4\u6267\u884c\u7ed3\u675f\u540e\u7684\u8fd4\u56de\u7ed3\u679c\u3002\u901a\u5e380\u8868\u793a\u6210\u529f\uff0c\u975e0\u5931\u8d25\u3002\n$$\uff1a\u76ee\u524dshell\u7684\u8fdb\u7a0b\u7f16\u53f7\u3002\n$!\uff1a\u4e0a\u4e00\u4e2a\u540e\u53f0\u7a0b\u5e8f\u7684\u8fdb\u7a0b\u7f16\u53f7\u3002\n\n$_\uff1a\u7528\u9014\u67093\u79cd\uff1a\n  1.  script\u6267\u884c\u65f6\uff0cbash\u7684\u7edd\u5bf9\u8def\u5f84\uff1b\n  2.  \u4e0a\u4e00\u4e2a\u547d\u4ee4\u6267\u884c\u65f6\uff0c\u6700\u540e\u4e00\u4e2a\u4f4d\u7f6e\u53c2\u6570\uff1b\n  3.  \u68c0\u67e5\u90ae\u4ef6\u65f6\uff0c\u503c\u4e3a\u90ae\u4ef6\u6587\u4ef6\u540d\u3002\n<\/code><\/pre>\n
\u8c03\u6574\u53d8\u91cf\u5c5e\u6027<\/h3>\n
readonly\u7528\u6cd5<\/h4>\n
readonly \u7528\u4e8e\u8bbe\u7f6e\u53ea\u8bfb\u53d8\u91cf\u3002
\nreadonly \u53d8\u91cf\u540d<\/code>
\nreadonly -f \u51fd\u6570\u540d<\/code>
\nreadonly -a \u6570\u7ec4\u540d<\/code><\/p>\n
declare\u7528\u6cd5<\/h4>\n
\n\u9009\u9879        \u7528\u9014                               \u8303\u4f8b\n-p        \u663e\u793a\u53d8\u91cf\u5c5e\u6027                      declare -p x\n-a        \u53d8\u91cf\u662f\u4e2a\u6570\u7ec4                      declare -a arr\n-f        \u641c\u7d22\u547d\u4ee4\u65f6\uff0c\u53ea\u627e\u51fd\u6570          declare -f showit\n-i        \u53d8\u91cf\u662f\u6574\u6570                          declare -i intvar\n-F        \u663e\u793a\u6240\u6709\u51fd\u6570\u540d\u79f0\u53ca\u5176\u5c5e\u6027    declare -F\n-r        \u8bbe\u5b9a\u53ea\u8bfb\u53d8\u91cf                      declare -r a\n-t        \u8bbe\u7f6e\u53d8\u91cf\u5177\u6709trace\u5c5e\u6027         declare -t xyz=11\n-x        \u8bbe\u4e3a\u73af\u5883\u53d8\u91cf                     declare -x PATH\n<\/code><\/pre>\n
\u4e3e\u4f8b<\/h4>\n
\u4ee3\u7801\uff1a<\/p>\n
\nvar=\"i am user defined variable .\"\nvartoo=\"$var too .\"\necho \"lets see their value, var:\\\"$var\\\", vartoo:\\\"${vartoo}\\\"\"\necho 'we cannot see their value, var:\\\"$var\\\", vartoo:\\\"${vartoo}\\\"'\n\nunset vartoo\necho \"after unset vartoo, lets see their value, var:\\\"$var\\\", vartoo:\\\"${vartoo}\\\"\"\n\ndeclare -i int=123\necho \"i am int type value is : $int\"\nint=\"given\"\necho \"after giving a string value, what is int value: $int\"\n\n<\/code><\/pre>\n
\u7ed3\u679c\uff1a<\/p>\n
\nlets see their value, var:\"i am user defined variable .\", vartoo:\"i am user defined variable . too .\"\nwe cannot see their value, var:\\\"$var\\\", vartoo:\\\"${vartoo}\\\"\nafter unset vartoo, lets see their value, var:\"i am user defined variable .\", vartoo:\"\"\ni am int type value is : 123\nafter giving a string value, what is int value: 0\n<\/code><\/pre>\n
\u6570\u7ec4<\/h2>\n
bash\u6570\u7ec4\u7684\u5143\u7d20\u4e2a\u6570\u6ca1\u6709\u9650\u5236\uff0c\u7d22\u5f15\u4ece0\u5f00\u59cb\uff0c\u4e0d\u4e00\u5b9a\u8981\u8fde\u7eed\u3002<\/p>\n
\u5efa\u7acb\u6570\u7ec4\uff1a<\/h3>\n
\u4e00\u6b21\u8bbe\u5b9a\u6bcf\u4e2a\u5143\u7d20\u503c\uff1a B=(2 3 5 4)<\/code>\uff0c\u5143\u7d20\u4e4b\u95f4\u7528\u7a7a\u683c\u5206\u9694\u3002
\n\u6307\u5b9a\u4e2a\u522b\u5143\u7d20\u7684\u7d22\u5f15\uff1a C=([3]=77  [1]=88  [5]=12)<\/code>\u3002
\n\u6307\u5b9a\u67d0\u4e00\u5143\u7d20\u7d22\u5f15\uff0c\u5176\u4f59\u7531\u7cfb\u7edf\u63a5\u7eed\uff1a E=(124  [8]=188  266)<\/code>\u3002<\/p>\n
\u53d6\u503c<\/h3>\n
${\u6570\u7ec4\u540d[\u7d22\u5f15]}<\/code>\uff1a \u53d6\u5143\u7d20\u503c\u3002<\/p>\n
${arr[@]}<\/code>\uff1a\u4e00\u6b21\u53d6\u51fa\u6570\u7ec4\u6240\u6709\u5143\u7d20\uff0c\u4ee5\u7a7a\u767d\u5206\u9694\u6bcf\u4e2a\u5143\u7d20\uff1b\u5982\u679c\u5143\u7d20\u662f\u5b57\u7b26\u4e32\uff0c\u4e14\u503c\u542b\u6709\u7a7a\u683c\uff0c\u5e94\u8be5\u901a\u8fc7\u6570\u7ec4\u7684\u7d22\u5f15\u5217\u8868\u8fdb\u884c\u904d\u5386\uff08\u5e94\u8be5\u603b\u662f\u901a\u8fc7\u7d22\u5f15\u5217\u8868\u8fdb\u884c\u904d\u5386<\/strong>\uff09\u3002
\n${arr[*]}<\/code>\uff1a\u4e00\u6b21\u53d6\u51fa\u6570\u7ec4\u6240\u6709\u5143\u7d20\uff0c\u8fde\u63a5\u6210\u4e00\u4e2a\u5b57\u7b26\u4e32\u3002<\/p>\n
\u53d6\u6570\u7ec4\u7d22\u5f15\u5217\u8868<\/h4>\n
${!\u6570\u7ec4\u53d8\u91cf[@]}<\/code>  \u6216  ${!\u6570\u7ec4\u53d8\u91cf[*]}<\/code>
\n\u628a\u6570\u7ec4\u53d8\u91cf\u7684\u6240\u6709\u7d22\u5f15\u5217\u51fa\uff0c\u5404\u7d22\u5f15\u503c\u4e4b\u95f4\u7528$IFS<\/code>\u5b9a\u4e49\u7684\u7b2c\u4e00\u4e2a\u5206\u9694\u7b26\u9694\u5f00\u3002<\/p>\n
\u8ba1\u7b97\u6570\u7ec4\u957f\u5ea6\uff1a  ${#arr[@]}  \u6216  ${#arr[*]}<\/code>
\n\u8ba1\u7b97\u6570\u7ec4\u67d0\u4e2a\u5143\u7d20\u7684\u957f\u5ea6\uff1a  ${#arr[\u7d22\u5f15]}<\/code><\/p>\n
\u53d6\u6d88\u6570\u7ec4\u6216\u6570\u7ec4\u5143\u7d20<\/h3>\n
unset \u6570\u7ec4\u540d<\/code>
\nunset \u6570\u7ec4\u540d[\u7d22\u5f15]<\/code><\/p>\n
\u4e3e\u4f8b<\/h3>\n
\u4ee3\u7801\uff1a<\/p>\n
\narr=(3 2 404 0 5)\necho \"arr length is ${#arr[@]},  ${#arr[*]}, length of element 2 is ${#arr[2]}\"\n\nunset arr[2]\necho \"after unset arr[2], arr length is ${#arr[@]},  ${#arr[*]}, length of element 2 is ${#arr[2]}\"\n\narr2=([3]=\"x y z\" [1]=1 [5]=911)\necho -n \"iterate arr2 element set: \"\nfor i in ${arr2[@]}\ndo\n    echo -n $i \",,\"\ndone\necho \"\"\n\necho -n \"iterate arr2 by index set : \"\nfor i in ${!arr2[@]}\ndo\n    printf \"%s,\" \"${arr2[$i]}\"\ndone\necho \"\"\n<\/code><\/pre>\n
\u7ed3\u679c\uff1a<\/p>\n
\narr length is 5,  5, length of element 2 is 3\nafter unset arr[2], arr length is 4,  4, length of element 2 is 0\niterate arr2 element set: 1 ,,x ,,y ,,z ,,911 ,,\niterate arr2 by index set : 1,x y z,911,\n<\/code><\/pre>\n
here document<\/h2>\n
\u57fa\u672c\u8bed\u6cd5<\/h3>\n
\n\u547d\u4ee4 << \u6807\u8bb0\n........content ...\n\u6807\u8bb0\n<\/code><\/pre>\n
\u8fd9\u6837\u4f1a\u628a\u547d\u4ee4\u548c\u6807\u8bb0\u4e4b\u95f4\u7684\u5185\u5bb9\uff0c\u5229\u7528\u8f6c\u5411\u8f93\u5165\u7684\u65b9\u5f0f\u4ea4\u7ed9\u8be5\u547d\u4ee4\u53bb\u5904\u7406\u3002<\/p>\n
\u6807\u8bb0\u53ef\u4ee5\u662f\u4efb\u4f55\u5b57\u7b26\u4e32\uff0c\u5c3d\u91cf\u9009\u7528\u4e0d\u5e38\u7528\u7684\u5b57\u7b26\u7ec4\u5408\uff0c\u907f\u514d\u8be5\u5b57\u7b26\u4e32\u51fa\u73b0\u5728\u8f93\u5165\u7684\u5185\u5bb9\u4e2d\u9020\u6210bash\u8bef\u5224\u3002<\/p>\n
bash\u652f\u6301\u53d8\u91cf\u66ff\u6362\uff0c\u5bf9\u6807\u8bb0\u52a0\u4e0a\u5355\u5f15\u53f7\u53ef\u5173\u95ed\u53d8\u91cf\u66ff\u6362\uff08$var<\/code>\uff09\uff0c\u4f46\u547d\u4ee4\u6269\u5c55\uff08\u53cd\u5f15\u53f7\u6269\u5c55\uff09\u4ecd\u7136\u662f\u53ef\u4ee5\u7684\u3002<\/p>\n
bash\u4e2d:<\/code>\u547d\u4ee4\u8868\u793a\u4ec0\u4e48\u4e5f\u4e0d\u505a\uff0c\u6240\u4ee5\u53ef\u4ee5\u7ed3\u5408here document\u8fdb\u884c\u6ce8\u91ca\u3002<\/p>\n
\u5728\u6807\u8bb0\u524d\u52a0\u4e0a-<\/code>\uff0c\u8868\u793a\u6291\u5236\u5404\u884c\u9996TAB\u7684\u4f5c\u7528\u3002-<\/code>\u4e0e<<<\/code>\u53ca\u6807\u8bb0\u4e4b\u95f4\u4e0d\u80fd\u6709\u7a7a\u683c\u3002<\/strong><\/p>\n
\u4e3e\u4f8b<\/h3>\n
\n: << coment_label\n        comment line 1\n        comment line 2\ncoment_label\n\nsh <<-cmd_label\n        echo \"call date command from here document :`date`\"\n        echo \"use var replace from here document :$var\"\ncmd_label\n\nsh <<-'cmd_label'\n        echo \"call date command from here document :`date`\"\n        echo \"use var replace from here document :$var\"\ncmd_label\n<\/code><\/pre>\n
\u53d8\u91cf\u6269\u5c55<\/h2>\n
\n\n\u6761\u4ef6\u5f0f                    \u76ee\u7684                                    \u5904\u7406\n${var:-\u9ed8\u8ba4\u503c}          \u56de\u4f20\u7684\u7ed3\u679c\u4e00\u5b9a\u8981\u6709\u503c           \u5982\u679cvar\u4e0d\u5b58\u5728\u6216\u4e3a\u7a7a\u503c\uff0c\u8fd4\u56de\u9ed8\u8ba4\u503c\uff0c\u5426\u5219\u8fd4\u56de\u53d8\u91cf\u503c\u3002\n${var:=\u9ed8\u8ba4\u503c}        \u7ed9\u7a7a\u503c\u53d8\u91cf\u8bbe\u7f6e\u4e00\u4e2a\u9ed8\u8ba4\u503c      \u5982\u679cvar\u4e0d\u5b58\u5728\u6216\u4e3a\u7a7a\u503c\uff0c\u628avar\u8bbe\u4e3a\u9ed8\u8ba4\u503c\u3002\n${var:?\u9519\u8bef\u4fe1\u606f}      \u68c0\u67e5\u6761\u4ef6\u662f\u5426\u5b8c\u5907                  \u5982\u679cvar\u4e0d\u5b58\u5728\u6216\u4e3a\u7a7a\u503c\uff0c\u663e\u793a'\u53d8\u91cf\u540d\u79f0\uff1a\u63d0\u793a\u4fe1\u606f\uff0c\u505c\u6b62\u6267\u884cscript\u3002\n${var:+\u9ed8\u8ba4\u503c}        \u5224\u65ad\u67d0\u4e8b\u662f\u5426\u4e3a\u771f                  Var\u5b58\u5728\u4e14\u975e\u7a7a\uff0c\u8fd4\u56de\u9ed8\u8ba4\u503c\uff0c\u5426\u5219\u8fd4\u56de\u53d8\u91cf\u503c\u3002\n<\/code><\/pre>\n
\u5728\u4e0a\u8868\u5404\u5f0f\u4e2d\uff0c\u82e5\u79fb\u9664:<\/code>\uff0c\u5219\u53ea\u6d4b\u8bd5\u5b58\u5728\u6027\uff0c\u4e0d\u6d4b\u7a7a\u503c\u3002<\/p>\n
\u8bb0\u5fc6\u6cd5\uff1a<\/p>\n
\n:      \u7a7a          \u6d4b\u7a7a\u503c\n-      \u8d1f\u5411       \u6d4b\u4e0d\u5b58\u5728\n=     \u8bbe\u7f6e       \u7ed9\u7a7a\u503c\u53d8\u91cf\u8bbe\u4e00\u4e2a\u9ed8\u8ba4\u503c\n?     \u6709\u95ee\u9898     \u68c0\u67e5\u6761\u4ef6\u662f\u5426\u5b8c\u5907\u540e\u518d\u6267\u884c\n+     \u6b63\u5411       \u6d4b\u8bd5\u5b58\u5728\n\n<\/code><\/pre>\n
\u53d8\u91cf\u6269\u5c55<\/h3>\n
\u5b57\u7b26\u4e32\u7684\u4f4d\u7f6e\u4e0b\u6807\u75310\u5f00\u59cb\u3002<\/p>\n
\u53d6\u90e8\u5206\u4f4d\u7f6e\u53c2\u6570<\/h4>\n
${@:\u8d77\u59cb\u4f4d\u7f6e}<\/code>
\n${@:\u8d77\u59cb\u4f4d\u7f6e:\u4e2a\u6570}<\/code><\/p>\n
\u53d6\u5b50\u4e32<\/h4>\n
${var:\u8d77\u59cb\u4f4d\u7f6e}<\/code>
\n${var:\u8d77\u59cb\u4f4d\u7f6e:\u957f\u5ea6}<\/code><\/p>\n
\u8ba1\u7b97\u5b57\u7b26\u4e32\u957f\u5ea6<\/h4>\n
${#\u53d8\u91cf\u540d}<\/code>\u6216expr length \"$\u53d8\u91cf\u540d\"<\/code>\u3002<\/p>\n
\u5b57\u7b26\u4e32\u622a\u53d6<\/h4>\n
${\u53d8\u91cf#\u6837\u5f0f}<\/code>\uff1a\u4ece\u7b2c\u4e00\u4e2a\u5b57\u7b26\u5f00\u59cb\u5339\u914d\uff0c\u5220\u9664\u6700\u77ed\u5339\u914d\u3002
\n${\u53d8\u91cf##\u6837\u5f0f}<\/code>\uff1a\u4ece\u7b2c\u4e00\u4e2a\u5b57\u7b26\u5f00\u59cb\u5339\u914d\uff0c\u5220\u9664\u6700\u957f\u5339\u914d\u3002
\n${\u53d8\u91cf%\u6837\u5f0f}<\/code>\uff1a\u4ece\u6700\u540e\u4e00\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c\u5220\u9664\u6700\u77ed\u5339\u914d\u3002
\n${\u53d8\u91cf%%\u6837\u5f0f}<\/code>\uff1a \u4ece\u6700\u540e\u4e00\u4e2a\u5b57\u7b26\u5f00\u59cb\uff0c\u5220\u9664\u6700\u957f\u5339\u914d\u3002<\/p>\n
\u5982\u679c\u7b2c\u4e00\u4e2a\u5b57\u7b26\u6216\u6700\u540e\u4e00\u4e2a\u5b57\u7b26\u5f00\u59cb\u7684\u5b57\u7b26\u4e32\u4e0e\u6837\u5f0f\u4e0d\u5339\u914d\uff0c\u5219\u4e0d\u622a\u53d6\u3002<\/p>\n
\u4e00\u79cd\u8bb0\u5fc6\u65b9\u6cd5\uff1a\u5728\u952e\u76d8\u4e0a#<\/code>\u5728%<\/code>\u7684\u5de6\u8fb9\uff0c\u6240\u4ee5#<\/code>\u662f\u4ece\u5de6\u5f00\u59cb\uff0c%<\/code>\u662f\u4ece\u53f3\u5f00\u59cb\uff1b%<\/code>\u6bd4%%<\/code>\u77ed\uff0c\u6240\u4ee5%<\/code>\u662f\u6700\u77ed\u5339\u914d\uff0c%%<\/code>\u662f\u6700\u957f\u5339\u914d\u3002<\/p>\n
\u5b57\u7b26\u4e32\u66ff\u6362<\/h4>\n
${var\/pattern\/replace_str}<\/code>\uff1a\u53ea\u66ff\u6362\u7b2c\u4e00\u4e2a\u6700\u957f\u5339\u914d\u3002
\n${var\/\/pattern\/replace_str}<\/code>\uff1a\u66ff\u6362\u6240\u6709\u7684\u6700\u957f\u5339\u914d\u3002
\n${var\/#pattern\/replace_str}<\/code>\uff1a\u53ea\u4ecevar\u5f00\u5934\u5339\u914d\uff0c\u7528replace_str\u66ff\u6362\u6700\u957f\u5339\u914d\u3002
\n${var\/%pattern\/replace_str}<\/code>\uff1a\u53ea\u4ecevar\u7ed3\u5c3e\u5339\u914d\uff0c\u7528replace_str\u66ff\u6362\u6700\u957f\u5339\u914d\u3002
\nreplace_str\u53ef\u4ee5\u662f\u53d8\u91cf\uff0c\u5982\uff1a${var\/pattern\/var2}<\/code><\/p>\n
\u4e0a\u8ff0\u66ff\u6362\u4e32\u4e3a\u7a7a\u5219\u8868\u793a\u5220\u9664\u5339\u914d\u3002<\/p>\n
\u4e3e\u4f8b<\/h3>\n
\u4ee3\u7801\uff1a<\/p>\n
\nstr=\"hello world .\"\necho \"str=\\\"${str}\\\",length=${#str}\" ',${str:4}=' \"\\\"${str:4}\\\"\" ',${str:4:4}=' \"\\\"${str:4:5}\\\"\"\n\nstr2=\"xx x\"\necho \"\\\"${str\/e*o\/$str2}\\\", \\\"${str\/e*o\/------}\\\", \\\"${str\/e*o\/}\\\"\"\necho \"${str\/#h*o \/abc},   ${str\/%w*d .\/$str2} \"\n\necho '${str#e*o}=' \"\\\"${str#e*o}\\\"\" ',${str##e*o}=' \"\\\"${str##e*o}\\\"\"\necho '${str#h*o}=' \"\\\"${str#h*o}\\\"\" ',${str##h*o}=' \"\\\"${str##h*o}\\\"\"\necho '${str%w*o}=' \"\\\"${str%w*o}\\\"\" ',${str%%w*o}=' \"\\\"${str%%w*o}\\\"\"\necho '${str%w*.}=' \"\\\"${str%w*.}\\\"\" ',${str%%w*.}=' \"\\\"${str%%w*.}\\\"\"\n<\/code><\/pre>\n
\u7ed3\u679c\uff1a<\/p>\n
\nstr=\"hello world .\",length=13 ,${str:4}= \"o world .\" ,${str:4:4}= \"o wor\"\n\"hxx xrld .\", \"h------rld .\", \"hrld .\"\nabcworld .,   hello xx x\n${str#e*o}= \"hello world .\" ,${str##e*o}= \"hello world .\"\n${str#h*o}= \" world .\" ,${str##h*o}= \"rld .\"\n${str%w*o}= \"hello world .\" ,${str%%w*o}= \"hello world .\"\n${str%w*.}= \"hello \" ,${str%%w*.}= \"hello \"\n<\/code><\/pre>\n
\u53d6\u53d8\u91cf\u540d\u79f0\u5217\u8868<\/h4>\n
${!\u5f00\u5934\u5b57\u7b26\u4e32@}<\/code>  \u6216  ${!\u5f00\u5934\u5b57\u7b26\u4e32*}<\/code>
\n\u628a\u6240\u6709\u4ee5\u6307\u5b9a\u5b57\u7b26\u4e32\u5f00\u5934\u7684\u53d8\u91cf\u540d\u5217\u51fa\uff0c\u5404\u53d8\u91cf\u4e4b\u95f4\u7528$IFS<\/code>\u5b9a\u4e49\u7684\u7b2c\u4e00\u4e2a\u5206\u9694\u7b26\u9694\u5f00\u3002<\/p>\n
\u547d\u4ee4\u66ff\u6362<\/h3>\n
\u547d\u4ee4\u66ff\u6362\u662f\u628a\u547d\u4ee4\u6267\u884c\u540e\u7684\u6807\u51c6\u8f93\u51fa\u653e\u5165\u53d8\u91cf\u4e2d\u3002<\/p>\n
\nvar=$(\u547d\u4ee4)\nvar=`\u547d\u4ee4`\n<\/code><\/pre>\n
\u5728\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u9ed8\u8ba4\u4f1a\u81ea\u52a8\u5220\u9664\u547d\u4ee4\u7ed3\u679c\u91cc\u7684\u6362\u884c\u7b26\u3002<\/p>\n
\u7b97\u672f\u8fd0\u7b97<\/h2>\n
\n\u540d\u79f0                           \u8bed\u6cd5                              \u8303\u4f8b\n\u7b97\u672f\u6269\u5c55                     $((\u7b97\u672f\u5f0f))                     r=$((2+5*8))  \u5982\u679c\u8868\u8fbe\u5f0f\u6709\u53d8\u91cf\uff0c\u53d8\u91cf\u540d\u524d\u4e0d\u8981\u52a0$\n\u4f7f\u7528\u5916\u90e8\u7a0b\u5e8fexpr         expr \u7b97\u672f\u5f0f                     r=`expr 4+5`\n\u4f7f\u7528$[]                      $[\u7b97\u672f\u5f0f]                        R=$[4+5]\n\u4f7f\u7528\u5185\u7f6e\u547d\u4ee4declare     declare -i var=\u7b97\u672f\u5f0f         declare -i r=8+6\n\u4f7f\u7528\u5185\u7f6e\u547d\u4ee4let           let \u7b97\u672f\u5f0f                        let r=5+6\n<\/code><\/pre>\n
\u5728\u6c42\u503c\u65f6\uff0c\u5982\u679c\u53d8\u91cf\u4e0d\u5b58\u5728\u6216\u7a7a\u503c\uff0c\u5219\u5176\u503c\u4e3a0.<\/p>\n
\u7528expr<\/code>\u505a\u7b97\u672f\u8fd0\u7b97\u65f6\uff0c\u5982\u679c\u8868\u8fbe\u5f0f\u91cc\u542b\u6709shell\u7684\u7279\u6b8a\u5b57\u7b26\uff0c\u9700\u8981\u8fdb\u884c\u8f6c\u4e49\u3002expr\u5728\u6211\u7684ubuntu12.04 vps\u4e0a\u6ca1\u6548\u679c\u3002<\/strong><\/p>\n
\u4f7f\u7528declare<\/code>\u3001let<\/code>\u7684\u6ce8\u610f\u4e8b\u9879\uff1a
\n\u7b97\u5f0f\u4e2d\uff0c\u8fd0\u7b97\u7b26\u548c\u64cd\u4f5c\u6570\u4e4b\u95f4\u4e0d\u53ef\u4ee5\u6709\u7a7a\u683c\uff0c\u8981\u7d27\u5bc6\u8fde\u63a5\uff1b
\n\u7279\u6b8a\u7b26\u53f7\u4e0d\u5fc5\u4f7f\u7528\\<\/code>\u8f6c\u4e49\uff1b
\n\u7b97\u5f0f\u4e2d\u53ef\u5305\u542b\u5176\u4ed6\u53d8\u91cf\uff0c\u53d8\u91cf\u524d\u4e0d\u5fc5\u52a0$<\/code>\u3002<\/p>\n
\u4ece\u5404\u79cd\u9650\u5236\u6765\u770b\uff0c\u8fd8\u662f\u4f7f\u7528$((expression))<\/code>\u6700\u597d\u3002<\/p>\n
\u4e3e\u4f8b<\/h2>\n
\u4ee3\u7801\uff1a<\/p>\n
\ndeclare -i int=123\ndeclare -i int2=123*2\n\nr=$(( int * 3 ))\nr4=$[$int * 4]\nr5=`expr 4*5`\nlet r6=$int*6\n#r5=`expr $int*5`\necho '$int=' $int '$,int2=' $int2 ',$r=' $r\necho '$r4=' $r4 ',$r5=' $r5 ',$r6=' $r6\n<\/code><\/pre>\n
\u7ed3\u679c\uff1a<\/p>\n
\nint= 123 $,int2= 246 ,$r= 369\n$r4= 492 ,$r5= 4*5 ,$r6= 738\n<\/code><\/pre>\n\n
\u6b22\u8fce\u5173\u6ce8\u6211\u7684\u5fae\u4fe1\u516c\u4f17\u53f7: coderbee\u7b14\u8bb0<\/strong>\uff0c\u53ef\u4ee5\u66f4\u53ca\u65f6\u56de\u590d\u4f60\u7684\u8ba8\u8bba\u3002<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
\u53d8\u91cf \u53d8\u91cf\u662f\u4ec0\u4e48 \u5728Bash shell\u4e2d\uff0c\u53ea\u6709\u4e00\u79cd\u6570\u636e\u578b\u6001\uff1a\u4ee5\u5b57\u7b26\u7ec4\u6210\u7684\u5b57\u7b26\u4e32 … \u7ee7\u7eed\u9605\u8bfb →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[35,36],"_links":{"self":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/101"}],"collection":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/comments?post=101"}],"version-history":[{"count":4,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/101\/revisions"}],"predecessor-version":[{"id":109,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/posts\/101\/revisions\/109"}],"wp:attachment":[{"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/media?parent=101"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/categories?post=101"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/coderbee.net\/index.php\/wp-json\/wp\/v2\/tags?post=101"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}