使用!<number>来重新运行历史记录中的特定命令。例如,如果您要重新运行编号为123的命令,请输入!123。 使用!!来重新运行上一个命令。例如,如果您要重新运行上一个命令,请输入!!。 使用!<string>来重新运行最近一个以特定字符串开头的命令。例如,如果您要重新运行最近一个以git开头的命令,请输入!git。 如果您需要...
To begin with, we can use sed to add a thousands separator. The sed command enables us to perform text transformations using regular expressions. We can use it to insert commas as a thousands separator within a number: $ echo "123456789" | sed ':a;s/\B[0-9]\{3\}\>/,&/;ta' 12...
export export命令将会使得被 export 的变量在运行的脚本(或shell)的所有的子进程中都可用. 不幸...
The code runs the “echo” statement 10 times with its iteration number as expected. $ bash bash.sh Example 04: Another unique way to define the “for” loop is using the “seq” expression in it. So, open the same file and add the bash extension to it. The syntax of the “for”...
$ time (sum=0;fornumberin`catnumbers.csv`;dosum=`expr$sum+$number`;done;echo"Total is:$sum") Total is: 49471228 real 212m48.418s user 7m19.375s sys 145m48.203s The processing was terribly slow. With theexprcommand, it took over 3.5 hours to add a million numbers.Notably, theexprut...
A variable in bash can contain a number, a character, a string of characters, etc. You have no need to declare a variable, just assigning a value to its reference will create it.Example:str="hello world"The above line creates a variable str and assigns "hello world" to it. The value...
0)break;;#输入数字非1-4的提示*)echo"please input number is [1-4]"esac ### 14.接受系统当前用户名为参数,判断用户 judgeUser.sh #!/bin/bash#接受系统当前用户名为参数;判断其为管理员root,系统用户system,普通用户user;userid=$(id-u)if[$userid-eq 0 ];thenecho"root"elif[$userid-gt 0 -...
perlnumber(1) perlobj(1) perlop(1) perlopenbsd(1) perlopentut(1) perlos2(1) perlos390(1) perlos400(1) perlpacktut(1) perlperf(1) perlplan9(1) perlpod(1) perlpodspec(1) perlpolicy(1) perlport(1) perlpragma(1) perlqnx(1) perlre(1) perlreapi(1) perlrebackslash(1) perlre...
hadolint.yaml added hadolint.yaml Oct 1, 2019 hadoop_random_node.sh updated hadoop_random_node.sh Jan 17, 2020 hdfs_checksum.sh added see also note and link to hadoop_hdfs_files_native_checksums.jy Nov 29, 2019 hdfs_checksum_crc.sh added see also note and link to hadoop_hdfs_files_nati...
本章节设计的命令:id useradd deluser usermod chmod su sudo chown passwd 在UNIX安全模型中,一个用户可以对文件或者目录有控制权,即owner。用户可以划归到某一个组中,如果改组对文件或者目录有控制权,那么其组内的用户均继承该控制权。那么除了用户自己和用户所在的组,剩余的均称为其它用户和其它用户组,拥有...