清单5-2。checkarg,如果参数未设置或为空,退出 ## Check for unset arguments : ${1?An argument is required} \ ${2?Two arguments are required} ## Check for empty arguments : ${1:?A non-empty argument is required} \ ${2:?Two no
then make that arg count from the right (subtract from the number of tokens, so that FIRST = -1 means the next to last token on the line). If LAST is `$' the last arg from STRING is used. */char*history_arg_extract(first, last,string)intfirst, last;constchar*string; {registerin...
echo "opt_f is $opt_f" echo "opt_l is $opt_l" echo "first arg is $1" echo "2nd arg is $2" 您可以这样运行该脚本: cmdparser -l hello -f -- -somefile1 somefile2 返回的结果是: opt_f is 1 opt_l is hello first arg is -somefile1 2nd arg is somefile2 1. 2. 3. 4....
possibly to the empty string"fiif [ -n "${JAIL-unset}" ]; then echo "JAIL is either unset or set to a non-empty string"fidone## syntax 1 ##if [[ -z "$variable" ]]; then echo "Empty $variable"else echo "Do whatever you want as ...
命令格式:echo arg 功能:在屏幕上显示出由arg指定的字串。 2.eval 命令格式:eval args 功能:当Shell程序执行到eval语句时,Shell读入参数args,并将它们组合成一个新的命令,然后执行。 3.exec 命令格式:exec命令参数 功能:当Shell执行到exec语句时,不会去创建新的子进程,而是转去执行指定的命令,当指定的命令执行...
### Example Script #!/usr/bin/env bash shopt -s extdebug debug() { echo "Func: ${BASH_ARGC[@]} ${BASH_ARGV[@]}" } echo "Main: ${BASH_ARGC[@]} ${BASH_ARGV[@]}" debug c ### Example output [me@linux ~]$ ./example-argdebug a b Main: 2 b a Func: 1 2 c b a ...
How to check if a command succeeds or failed? How to do string comparison and check if a string equals to a value? How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not ...
Given the recent swath of articles covering the fundamental aspects of Bash (listed at the end of this article), it’s inevitable that one of your ne...
urlopen.sh - opens the URL given as an arg, or first URL found from stdin or a given file. Uses the system's default browser vagrant_hosts.sh - generate /etc/hosts output from a Vagrantfile vagrant_total_mb.sh - calculate the RAM committed to VMs in a Vagrantfile See also Knowledge...
我将遍历字符串并检查每个键值对，它使用修改后的正则表达式-([a-zA-Z_0-9]+) ([^ ]+)，其中(...