使用文件中的选项执行bash命令

Question

我很难执行从文本文件中读取的bash命令（带有选项）。 在我的脚本中，有一个for循环，该循环从文件中读取命令，但出错：

cat com.txt
apt-get update

我的脚本：

for i in `cat com.txt` ; do sudo bash -c $i ; done;

显示的错误消息为：

apt 1.0.1ubuntu2 for amd64 compiled on Oct 28 2014 20:55:14
Usage: apt-get [options] command
       apt-get [options] install|remove pkg1 [pkg2 ...]
       apt-get [options] source pkg1 [pkg2 ...]

apt-get is a simple command line interface for downloading and
installing packages. The most frequently used commands are update
and install.

Commands:
   update - Retrieve new lists of packages
   upgrade - Perform an upgrade
   install - Install new packages (pkg is libc6 not libc6.deb)
   remove - Remove packages
   autoremove - Remove automatically all unused packages
   purge - Remove packages and config files
   source - Download source archives
   build-dep - Configure build-dependencies for source packages
   dist-upgrade - Distribution upgrade, see apt-get(8)
   dselect-upgrade - Follow dselect selections
   clean - Erase downloaded archive files
   autoclean - Erase old downloaded archive files
   check - Verify that there are no broken dependencies
   changelog - Download and display the changelog for the given package
   download - Download the binary package into the current directory

Options:
  -h  This help text.
  -q  Loggable output - no progress indicator
  -qq No output except for errors
  -d  Download only - do NOT install or unpack archives
  -s  No-act. Perform ordering simulation
  -y  Assume Yes to all queries and do not prompt
  -f  Attempt to correct a system with broken dependencies in place
  -m  Attempt to continue if archives are unlocatable
  -u  Show a list of upgraded packages as well
  -b  Build the source package after fetching it
  -V  Show verbose version numbers
  -c=? Read this configuration file
  -o=? Set an arbitrary configuration option, eg -o dir::cache=/tmp
See the apt-get(8), sources.list(5) and apt.conf(5) manual
pages for more information and options.
                       This APT has Super Cow Powers.
bash: update: command not found

Answer 1

在您的示例中，您没有执行整条线。 您只需执行apt-get （需要一个参数），然后update （这不是命令）。

只需在带有bash的文件内使用execute命令的source （不需要执行位）：

source com.txt

Answer 2

这是不使用for循环中的cat读取行的众多原因之一。 使用while read -r代替。

while read -r cmd; do
    sudo $cmd
done <com.txt

从您的示例来看， bash -c似乎是多余的，但这取决于您的命令以及在sudoers设置的特权。 对于更复杂的事情，您可能会遇到http://mywiki.wooledge.org/BashFAQ/050 ，并且source答案比可能的解决方法更有意义。