{"id":393,"date":"2021-07-28T16:26:05","date_gmt":"2021-07-28T08:26:05","guid":{"rendered":"http:\/\/egonlin.com\/?p=393"},"modified":"2023-01-28T14:41:23","modified_gmt":"2023-01-28T06:41:23","slug":"%e7%ac%ac%e4%b8%80%e8%8a%82%ef%bc%9aif%e5%88%a4%e6%96%ad","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=393","title":{"rendered":"\u7b2c\u4e00\u8282\uff1aif\u5224\u65ad"},"content":{"rendered":"

\u6d41\u7a0b\u63a7\u5236\u4e4bif\u5224\u65ad<\/h1>\n

\u4e00\uff1a\u5355\u5206\u652fif<\/h2>\n

\u8bed\u6cd5<\/p>\n

if \u6761\u4ef6;then\n    \u8981\u6267\u884c\u7684\u547d\u4ee41\n    \u8981\u6267\u884c\u7684\u547d\u4ee42\n    \u8981\u6267\u884c\u7684\u547d\u4ee43\n    ...\nfi\n\n# \u4e0a\u8ff0\u8bed\u6cd5\u53ef\u4ee5\u7528\u4e00\u884c\u4ee3\u7801\u4ee3\u66ff\n[ \u6761\u4ef6\u4fe1\u606f ] && xxx<\/code><\/pre>\n
\u793a\u4f8b<\/p>\n
[root@egon test]# cat disk_monitor.sh \n#!\/usr\/bin\/env bash\n\ndisk_use=$(df -P |grep '\/$' |awk '{print $5}' |awk -F% '{print $1}')\nif [ $disk_use -gt 10 ];then\n    echo "warning:Not enough hard disk space"\nfi\n[root@egon test]# . disk_monitor.sh \nwarning:Not enough hard disk space<\/code><\/pre>\n
\u6ce8\u610f\uff1aif \u6d4b\u8bd5\u4e2d\u8fd8\u53ef\u4ee5\u6267\u884c\u547d\u4ee4 \u6839\u636e\u547d\u4ee4\u7684\u8fd4\u56de\u503c\u505a\u5224\u65ad<\/p>\n
[root@egon ~]# if cd \/ ;then echo Y ;fi\nY\n[root@egon \/]# if grep -q root \/etc\/passwd ;then echo Y ;fi\nY<\/code><\/pre>\n
\u4e8c\uff1a\u53cc\u5206\u652fif<\/h2>\n
\u8bed\u6cd5<\/p>\n
if \u6761\u4ef6;then\n    \u8981\u6267\u884c\u7684\u547d\u4ee41\n    \u8981\u6267\u884c\u7684\u547d\u4ee42\n    \u8981\u6267\u884c\u7684\u547d\u4ee43\n    ...\nelse\n    \u8981\u6267\u884c\u7684\u547d\u4ee41\n    \u8981\u6267\u884c\u7684\u547d\u4ee42\n    \u8981\u6267\u884c\u7684\u547d\u4ee43\n    ...\nfi\n\n# \u4e0a\u8ff0\u8bed\u6cd5\u53ef\u4ee5\u7528\u4e00\u884c\u4ee3\u7801\u4ee3\u66ff\n[ \u6761\u4ef6\u4fe1\u606f ] && xxx || xxxx<\/code><\/pre>\n
\u793a\u4f8b<\/p>\n
#!\/bin\/bash\nusername='egon'\npassword='123'\nread -p 'user: ' name \nread -p 'passwd: ' passwd\n\nif [ $name = $username -a $passwd = $password ];then\n    echo 'login successful'\nelse\n    echo 'username or password err'\nfi<\/code><\/pre>\n
\u4e09\uff1a\u591a\u5206\u652fif<\/h2>\n
\u8bed\u6cd5\uff1a<\/p>\n
if \u6761\u4ef6;then\n    \u8981\u6267\u884c\u7684\u547d\u4ee41\n    \u8981\u6267\u884c\u7684\u547d\u4ee42\n    \u8981\u6267\u884c\u7684\u547d\u4ee43\n    ...\nelif \u6761\u4ef6;then\n    \u8981\u6267\u884c\u7684\u547d\u4ee41\n    \u8981\u6267\u884c\u7684\u547d\u4ee42\n    \u8981\u6267\u884c\u7684\u547d\u4ee43\n    ...\nelif \u6761\u4ef6;then\n    \u8981\u6267\u884c\u7684\u547d\u4ee41\n    \u8981\u6267\u884c\u7684\u547d\u4ee42\n    \u8981\u6267\u884c\u7684\u547d\u4ee43\n    ...\n...\nelse\n    \u8981\u6267\u884c\u7684\u547d\u4ee41\n    \u8981\u6267\u884c\u7684\u547d\u4ee42\n    \u8981\u6267\u884c\u7684\u547d\u4ee43\n    ...\nfi<\/code><\/pre>\n
\u793a\u4f8b1:\u731c\u5e74\u9f84<\/p>\n
======================\u7248\u672c1======================\n#!\/bin\/bash\nage=87\nread -p 'num: ' n\n\nif [ $n -eq $age ];then\n    echo 'you get it'\nelif [ $n -gt $age ];then\n    echo 'too big'\nelif [ $n -lt $age ];then\n    echo 'too small'\nfi\n\n======================\u7248\u672c2======================\n#!\/bin\/bash\n\nread -p ">>> " num\n\n[[ ! $num =~ ^[0-9]+$ ]] && echo "\u8bf7\u8f93\u5165\u6570\u5b57" && exit\n\nif [ $num -gt 18 ];then\n    echo "too big"\nelif [ $num -lt 18 ];then\n    echo "too small"\nelse\n    echo "you got it"\nfi\n<\/code><\/pre>\n
\u793a\u4f8b2\uff1a\u67e5\u8be2\u6210\u7ee9<\/p>\n
======================\u7248\u672c1======================\n#!\/bin\/bash\nread -p 'your score: ' score\n\nif [ $score -ge 90  ];then\n    echo '\u4f18\u79c0'\nelif [ $score -ge 70 -a $score -lt 90 ];then\n    echo '\u826f\u597d'\nelif [ $score -ge 60 -a $score -lt 70 ];then\n    echo '\u4e00\u822c'\nelif [ $score -lt 60 ];then\n    echo '\u8f83\u5dee'\nfi\n\n======================\u7248\u672c2======================\n#!\/bin\/bash\n\nread -p "your score>>> " score\n\n[[ ! $score =~ ^[0-9]+$ ]] && echo "\u8bf7\u8f93\u5165\u6570\u5b57" && exit\n\nif [ $score -ge 90 ];then\n    echo "\u4f18\u79c0"\nelif [ $score -ge 70 ];then\n    echo "\u826f\u597d"\nelif [ $score -ge 60 ];then\n    echo "\u4e00\u822c"\nelse\n    echo "\u8f83\u5dee"\nfi<\/code><\/pre>\n
\u793a\u4f8b3\uff1a\u5224\u65ad\u662f\u5426\u662f\u6570\u5b57<\/p>\n
read -p "\u8bf7\u8f93\u5165\u4e00\u4e2a\u6570\u503c: " num\n\nwhile :\ndo\n        if [[ $num =~ ^[0-9]+$ ]];then\n                break\n        else\n                read -p "\u4e0d\u662f\u6570\u5b57\uff0c\u8bf7\u91cd\u65b0\u8f93\u5165\u6570\u503c: " num\n        fi\ndone\n\necho "\u4f60\u8f93\u5165\u7684\u6570\u5b57\u662f: $num"<\/code><\/pre>\n
\u56db \u7ec3\u4e60<\/h2>\n
1\u3001\u7f16\u5199\u811a\u672c\uff0c\u547d\u4ee4\u884c\u4f20\u5165\u4e00\u4e2a\u6587\u4ef6\u8def\u5f84\uff0c\u5224\u65ad\u6587\u4ef6\u7684\u7c7b\u578b<\/p>\n
[root@localhost ~]# cat test_file.sh \n#!\/bin\/bash\nif [ -d $1 ]\n    then\n        echo "$1 is directory"\nelif [ -b $1 ]\n    then\n        echo "$1 is block"\nelif [ -f $1 ]\n    then\n        echo "$1 is regular file"\nelse\n        echo 'unknown'\nfi\n[root@localhost ~]# .\/test_file.sh \/etc\/passwd\n\/etc\/passwd is regular file<\/code><\/pre>\n
2\u3001\u68c0\u6d4b\u6307\u5b9a\u7684\u4e3b\u673a\u662f\u5426\u53ef\u4ee5ping\u901a\uff0c\u5fc5\u987b\u4f7f\u7528$1\u53d8\u91cf<\/p>\n
[root@egon test]# cat ping.sh \n#!\/bin\/bash\n\nping -c2 $1 &>\/dev\/null\nif [ $? -eq 0 ];then\n    echo "ok"\nelse\n    echo "down"\nfi\n[root@egon test]# chmod +x ping.sh \n[root@egon test]# .\/ping.sh 10.10.0.1\ndown\n[root@egon test]# <\/code><\/pre>\n
3\u3001\u5224\u65ad\u4e00\u4e2a\u7528\u6237\u662f\u5426\u5b58\u5728<\/p>\n
[root@egon test]# cat check_user.sh \n#!\/bin\/bash\n\nid $1 &> \/dev\/null\nif [ $? -eq 0 ];then\n    echo "user $1 exists"\nelse\n    echo "user $1 not exists"\nfi\n[root@egon test]# chmod +x check_user.sh \n[root@egon test]# .\/check_user.sh egon\nuser egon exists\n[root@egon test]# .\/check_user.sh xx\nuser xx not exists<\/code><\/pre>\n
4\u3001\u68c0\u6d4bhttpd\u8f6f\u4ef6\u662f\u5426\u5b89\u88c5\uff0c\u6ca1\u6709\u7684\u8bdd\u5219\u5b89\u88c5<\/p>\n
[root@egon test]# cat check_httpd.sh\n#!\/bin\/bash\n\nrpm -q httpd &>\/dev\/null\nif [ $? -eq 0 ];then\n    echo "\u5df2\u7ecf\u5b89\u88c5"\nelse\n    echo "\u6b63\u5728\u5b89\u88c5..."\n    yum install httpd -y &>\/dev\/null\nfi<\/code><\/pre>\n
5\u3001\u5224\u65ad80\u7aef\u53e3\u7684\u72b6\u6001,\u672a\u5f00\u542f\u5219\u91cd\u542f<\/p>\n
[root@egon test]# cat check_port.sh \n#!\/bin\/bash\n\nnetstat -an |grep LISTEN |grep '\\b80\\b' &>\/dev\/null\nif [ $? -eq 0 ];then\n    echo "80\u7aef\u53e3ok"\nelse \n    echo "80\u7aef\u53e3down"\n    echo "\u6b63\u5728\u91cd\u542f..."\n    systemctl restart httpd &> \/dev\/null\n    if [ $? -eq 0 ];then\n        echo "\u91cd\u542f\u6210\u529f"\n    else\n        echo "\u91cd\u542f\u5931\u8d25"\n    fi\nfi<\/code><\/pre>\n
6\u3001\u7f16\u5199\u76d1\u63a7\u811a\u672c\uff0c\u5982\u679c
\n\u6839\u5206\u533a\u5269\u4f59\u7a7a\u95f4\u5c0f\u4e8e10%
\n\u5185\u5b58\u7684\u53ef\u7528\u7a7a\u95f4\u5c0f\u4e8e30%
\n\u5411\u7528\u6237egon\u53d1\u9001\u544a\u8b66\u90ae\u4ef6\uff0c\u90ae\u4ef6\u7684\u5185\u5bb9\u5305\u542b\u4f7f\u7528\u7387\u76f8\u5173\u4fe1\u606f<\/p>\n
\u7b54\u6848<\/p>
<\/div>
\u67e5\u770b\u66f4\u591a<\/h2>
\u8054\u7cfb\u7ba1\u7406\u5458\u5fae\u4fe1tutu19192010\uff0c\u6ce8\u518c\u8d26\u53f7<\/p>\n<\/div>
<\/div>
<\/td><\/tr>
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<\/td><\/tr><\/tbody><\/table><\/form>
Register<\/a><\/div>
Forgotten username or password?<\/a><\/div>
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<\/div>","protected":false},"excerpt":{"rendered":"
\u6d41\u7a0b\u63a7\u5236\u4e4bif\u5224\u65ad \u4e00\uff1a\u5355\u5206\u652fif \u8bed\u6cd5 if \u6761\u4ef6;then \u8981\u6267\u884c\u7684\u547d\u4ee41 \u8981\u6267\u884c\u7684\u547d\u4ee42 \u8981\u6267\u884c\u7684\u547d\u4ee43 […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[2,61,451],"tags":[21,19,75,22,20],"_links":{"self":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/393"}],"collection":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=393"}],"version-history":[{"count":0,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/393\/revisions"}],"wp:attachment":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=393"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=393"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=393"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}