$3 $3" # 访问传入的参数 echo "the number of parameters: \$# $#" # 传入的参数数量 echo "all parameters: \$@ $@" # 每个参数作为独立字符串 echo "all parameters: \$* $*" # 所有参数合在一个字符串中 pwd # linux 打印当前路径的命令 echo "exit status of the previous command: \$?
tion,declareandtypeset makeeachname local,aswiththe local command, unless the -goptionissup‐ plied.Ifa variable nameisfollowedby=value, the valueofthe variableissettovalue.Whenus‐ ing -aor-Aandthe compound assignment syntaxtocreate array variables, additional attributesdonottakeeffectuntilsubsequent...
子串削除: {varilable#*pattern}: 查找variable中自左而右第一次被pattern匹配到的串,将此串及向左的所有内容都删除{varilable##*pattern}: 查找variable中自左而右最后一次被pattern匹配到的串,将此串及向左的所有内容都删除 {varilable%pattern*}:查找variable中自右而左第一次被pattern匹配到的串,将此串及...
forvariable in listdocommand1 command2 ...done 例如,以下脚本将打印 1 到 5: fori in{1..5}doecho$idone 以下是while循环的基本语法: while[condition]docommand1 command2 ...done 例如,以下脚本将打印 1 到 5: i=1while[$i-le5]doecho$i((i++))done 条件语句 Bash 支持if和case条件语句。
command结构可以将命令的输出赋值到一个变量中去。在后边的后置引用(backquotes)或后置标记(backticks)中也会讲解。 反引号中的命令会优先执行,如: 先创建了back目录,然后赋值test.sh到back目录 七,冒号(:) 1,空命令 等价于“NOP”(no op,一个什么也不干的命令)。也可以被认为与shell的内建命令true作业相同...
Single command output to a variable Bash commands can be used without any option and argument for those commands where these parts are optional. The following two examples show the uses of simple command substitution. Example#1: bash `date`command is used to show the current date and time. Th...
name="Marcela": This line declares a variable named 'name' and assigns it the value "Marcela". In Bash, variables are declared and assigned values without specific data type. echo "The value of the variable 'name' is: $name": This line uses the "echo" command to print a message to ...
Run the script using the following command: $ bash set1.bash Read the values of the variable using the “echo” command: $ echo $v1 $v2 $v3 The following output appears after executing the previous commands: Example 2: Using the Set Command with -C Option ...
A. If yourcommand_not_found_handlefunction is not intended to address (possibly missing) commands invoked during bash programmable completion functions, you can account for this in the function by, for example, testing if the$COMP_LINEvariable is set and taking appropriate action, typically returni...
precmdExecuted just before each prompt. Equivalent to PROMPT_COMMAND, but more flexible and resilient. Should output something like: elementz@Kashmir:~/git/bash-preexec (master)$ ls just typed ls bash-preexec.sh README.md test printing the prompt ...