In Bash, you can generate a random number using the built-in variable$RANDOM. It will return a random integer between 0 and 32767 which you can attach to a variable or print it to terminal with the syntaxecho $RANDOM. This variable provides a simple and efficient way to create random nu...
1 RANDOM使用shell变量$RANDOM,echo $RANDOM 生成的是整数随机数范围为: 0 - 32767 (带符号的16位整数). 这个是最为调用的方式。使用BASH内置的$RANDOM函数。 $ echo $RANDOM 26791 $ echo $RANDOM 140622 生成某…
/bin/bashrandom_number=`echo"scale=4 ;${RANDOM}/32767"| bc -l`# 生成0-1的随机数number=`echo"$random_number*100"| bc`echo$numbernumber_round1=`echo$number| xargsprintf"%.*f\n"0`echo$number_round1number_round2=`echo$number| xargsprintf"%.*f\n"1`echo$number_round2exit0 执行结果...
这是因为在系统某些服务也会需要调用Shell来做一些操作,这些服务不一定就会使用当前服务默认的Shell,而是使用/etc/shells中其他shell或/sbin/nologin这个shell,比如使用FTP这个服务你不会希望用户使用FTP以外的主机资源,所以就会使用/bin/nologin这个shell,可以简单把nologin理解为一个功能不齐全的shell...
$RANDOM:产生随机数 vim a.sh #运用脚本产生10个随机数 #!/bin/bash a=1 b=10 while [ $a -le $b ] do number=$RANDOM echo $number ((a++)) done [root@localhost ~]# chmod +x a.sh [root@localhost ~]# ./a.sh 17065 4080
shell脚本: #!/bin/bash SplitInteger() { let SIZE_BYTES=$SIZE_BYTES-$NUMBER*$minNum declare -a num_list num_list[0]=0 num_list[1]=$SIZE_BYTES let num=$NUMBER for i in $(seq 2 $num); do random_rate=`echo "scale=4 ; ${RANDOM}/32767" | bc -l` # 生成0-1的随机数 ...
这意味着number=$(( $RANDOM % 100 + 1 ))生成一个介于1到100之间的随机数。模运算符(%)返回余数除以两个数字之后。在这种情况下,Bash将一个随机数除以100,剩下的余数在零到99之间。通过将一个值加到这个值,就可以得到一个介于1到100之间的随机数。
$((a + 200)) # Add 200 to $a $(($RANDOM%200)) # Random number 0..199 查看命令 command -V cd #=> "cd is a function/alias/whatever" source 命令 source "${0%/*}/../share/foo.sh" 字符串转换 tr 命令 -c # Operations apply to characters not in the given set -d # Delete...
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impala_shell.sh - shortens impala-shell command to connect to Impala by parsing the Hadoop topology map and selecting a random datanode to connect to its Impalad, acting as a cheap CLI load balancer. For a real load balancer see HAProxy config for Impala (and many other Big Data & NoSQL...