bash 执行描述 shell 命令的字符串数组
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Execute an array of string describing shell command
提问by renard
I'm struggling to execute a set of command lines stored as strings in an array. My code looks like this :
我正在努力执行一组以字符串形式存储在数组中的命令行。我的代码如下所示：
arr=( "sudo apt-get update" "sudo apt-get install xxx" )
...
arr=( ${arr[@]} "ln -s /path1 /path2" )
etc...
# Then I loop on the array of command
for (( i = 0 ; i < ${#arr[@]} ; i++ ))
do
eval ${arr[$i]}
done
When it loops over the array, the array is larger than the number of command stored into it. As if the blank spaces in my strings split the array in more elements A typical ouput is such like
当它遍历数组时，数组大于存储在其中的命令数。好像我的字符串中的空格将数组拆分为更多元素一个典型的输出是这样的
usage: sudo -h | -K | -k | -L | -V
That means only 'sudo' is taken from within the string and I don't understand why!
这意味着只有 'sudo' 是从字符串中取出的，我不明白为什么！
Thanks
谢谢
回答by chown
Use ${#arr[@]}to get the number of items in the array (${arr[@]}gives the word count). Using either evalor back-ticks (`) to execute the command works:
使用${#arr[@]}得到数组中的项目数（${arr[@]}给人的字计数）。使用eval或反引号 ( `) 执行命令的工作原理是：
[ 15:20 jon@host ~ ]$ cat run_yum_test.sh
#!/bin/bash
declare -a arr=("sudo yum search zsh" "sudo yum list zsh")
for (( i = 0; i < ${#arr[@]} ; i++ )); do
printf "\n**** Running: ${arr[$i]} *****\n\n"
# Run each command in array
eval "${arr[$i]}"
### using back-ticks works also
#RESULT=`${arr[$i]}`
### Check if the command gave any output
#if [ -n "$RESULT" ]; then
# echo "$RESULT"
#fi
done
[ 15:20 jon@host ~ ]$ ./run_yum_test.sh
**** Running: sudo yum search zsh *****
[sudo] password for jon:
Loaded plugins: presto, refresh-packagekit
=========================================================================== Matched: zsh ===========================================================================
zsh-html.i686 : Zsh shell manual in html format
autojump-zsh.noarch : Autojump for zsh
fatrat-czshare.i686 : FatRat plugin enabling CZShare.com downloads and uploads
gromacs-zsh.noarch : GROMACS zsh support
python-twisted-core-zsh.i686 : Tab completion for Zsh and Twisted Core
zsh.i686 : A powerful interactive shell
environment-modules.i686 : Provides dynamic modification of a user's environment
plowshare.noarch : CLI downloader/uploader for some of the most popular file-sharing websites
**** Running: sudo yum list zsh *****
Loaded plugins: presto, refresh-packagekit
Available Packages
zsh.i686 4.3.10-6.fc13 updates
Edit (to answer your comment):
编辑（回答您的评论）：
To "extend" the array, put the original array (${arr[@]}) in quotes, like so:
要“扩展”数组，请将原始数组 ( ${arr[@]}) 放在引号中，如下所示：
arr=("sudo yum list zsh" "sudo yum search zsh")
arr=("${arr[@]}" "echo 'TEST'")
Here it is in action:
这是在行动：
[ 16:06 jon@host ~ ]$ cat run_yum_test.sh
#!/bin/bash
arr=("sudo yum list zsh" "sudo yum search zsh")
arr=("${arr[@]}" "echo 'TEST'")
for (( i = 0; i < ${#arr[@]} ; i++ )); do
printf "\n**** Running: ${arr[$i]} *****\n\n"
eval "${arr[$i]}"
done
[ 16:06 jon@host ~ ]$ ./run_yum_test.sh
**** Running: sudo yum list zsh *****
[sudo] password for jon:
Loaded plugins: presto, refresh-packagekit
Available Packages
zsh.i686 4.3.10-6.fc13 updates
**** Running: sudo yum search zsh *****
Loaded plugins: presto, refresh-packagekit
=========================================================================== Matched: zsh ===========================================================================
zsh-html.i686 : Zsh shell manual in html format
autojump-zsh.noarch : Autojump for zsh
fatrat-czshare.i686 : FatRat plugin enabling CZShare.com downloads and uploads
gromacs-zsh.noarch : GROMACS zsh support
python-twisted-core-zsh.i686 : Tab completion for Zsh and Twisted Core
zsh.i686 : A powerful interactive shell
environment-modules.i686 : Provides dynamic modification of a user's environment
plowshare.noarch : CLI downloader/uploader for some of the most popular file-sharing websites
**** Running: echo 'TEST' *****
TEST
