In Bash scripting, various methods can be followed to name a variable, i.e., only alphabets, alphabets with numbers, and alphabets with numbers/underscore. Each method has some legal ways to name a variable in Bash. Moreover, the legal and illegal perspectives of each method are also explor...
grep -al 'Illegal variable name' /bin/* Run Code Online (Sandbox Code Playgroud) 并在/bin/csh 中找到该消息。当您发出命令时,您似乎正在运行csh而不是 bash。例如: csh $ echo `echo abc` abc csh $ echo $(echo abc) Illegal variable name. Run Code Online (Sandbox Code Playgroud)归档...
name='Bob; echo I am arbitrary code'; eval "user=$name" Even if you%qinput data before treating it as a variable name, illegal variable names in assignments cause bash to searchPATHfor a command: echo 'echo I am arbitrary code' > /usr/local/bin/a[1]=b; chmod +x /usr/local/bin...
For the shell's purposes, a variable is a parameter denoted by a name. A parameter is set if it has been assigned a value. The null string is a valid value. Once a variable is set, it may be unset only by using the unset builtin command (see name=[value] If value is not ...
bash: $9: unboundvariable 1. 2. 变量“$@”或者是“?*”将所有参数作为一个字符串返回。 当使用定位参数时,Bash并不区分它们是参数还是开关,对于脚本来说在命令行的每一个项目作为独立的参数来对待。 考虑一下下面的脚本,显示在列表9.1中: Listing 9.1 params.sh ...
long_variable_name_which_may_tell_you_something_about_its_purpose=1 一个变量的范围:你能从这里看到它吗? 默认情况下,变量的定义只有定义它的 shell(以及该 shell 的子 shell)知道。调用当前脚本的脚本不会知道这个变量,被当前脚本调用的脚本也不会知道这个变量,除非它被导出到环境。 环境是一个形式为name...
bash: $9: unboundvariable 变量“$@”或者是“?*”将所有参数作为一个字符串返回。 当使用定位参数时,Bash并不区分它们是参数还是开关,对于脚本来说在命令行的每一个项目作为独立的参数来对待。 考虑一下下面的脚本,显示在列表9.1中: Listing 9.1 params.sh ...
Each time it is invoked, getopts places the next option in the shell variablename, initializingnameif it does not exist, and the index of the next argument to be processed into the variableOPTIND. OPTINDis initialized to 1 each time the shell or a shell script is invoked. ...
# add the filenames to a variable list FILES=$FILES" "$1 else echo "`basename $0`: Error cannot find the file $1" fi shift ;; esac done # no options given ... help the user if [ "$OPT" == "no" ]; then echo " try `basename $0` --help" ...
1. location [ = | ~ | ~* | ^~ ] uri { ... } 2. location @name { ... } ...