Question

我有一个检查环境的脚本，我想问您有关如何处理“找不到命令”错误的建议。

if (_Size == 2)
        return operator[](0) * operator[](3) - operator[](2) * operator[](1);

它显示echo "...RVM Version : $(rvm -v)" echo "...Node Version : $(node -v)" echo "...Ruby Version : $(ruby -v)" echo "...Bundler Version : $(bundle -v)" echo "...Passenger Version: $(passenger -v)"和node命令的“找不到命令”：

passenger

我不想显示错误，而是显示“未找到”，就像这样：

...RVM Version      : rvm 1.29.7 (latest) by Michal Papis
deploy_confirm.sh: line 10: node: command not found
...Node Version     : 
...Ruby Version     : ruby 2.6.0p0 (2018-12-25 revision 66547)
...Bundler Version  : Bundler version 2.0.1
deploy_confirm.sh: line 13: passenger: command not found
...Passenger Version:

Answer 1

使用2>/dev/null禁止显示错误消息，并使用||作为else的简写。如果命令a || b失败，b将运行a。

echo "...Login Shell User : $(whoami)"
echo "...RVM Version      : $(rvm -v 2>/dev/null || echo 'Not found')"
echo "...Node Version     : $(node -v 2>/dev/null || echo 'Not found')"
echo "...Ruby Version     : $(ruby -v 2>/dev/null || echo 'Not found')"
echo "...Bundler Version  : $(bundle -v 2>/dev/null || echo 'Not found')"
echo "...Passenger Version: $(passenger -v 2>/dev/null || echo 'Not found')"

Answer 2

包装器功能是一种获得自定义行为的简便方法，特别是在不希望在全局范围内更改行为的情况下（尤其是）。

or_not_found() {
  if type "$1" >/dev/null 2>&1; then # if given a valid command
    "$@"                             # run that command with original arguments
  else
    echo "Not found"  # write to stdout so it's captured by the command substitution
  fi
}

echo "...Login Shell User : $USER"  # much more efficient than calling whoami
echo "...RVM Version      : $(or_not_found rvm -v)"
echo "...Node Version     : $(or_not_found node -v)"
echo "...Ruby Version     : $(or_not_found ruby -v)"
echo "...Bundler Version  : $(or_not_found bundle -v)"
echo "...Passenger Version: $(or_not_found passenger -v)"

Answer 3

如果您使用bash> = 4.0，请在第一行echo之前插入此行：

command_not_found_handle() { echo "not found"; return 127; }

然后在最后echo行之后插入此字符以摆脱此功能：

unset command_not_found_handle

输出，例如：

...RVM Version      : not found
...Node Version     : v4.2.6
...Ruby Version     : ruby 2.3.1p112 (2016-04-26) [x86_64-linux-gnu]
...Bundler Version  : not found
...Passenger Version: not found

如何处理bash中的“找不到命令”

3 个答案: