如何將命令存儲在shell腳本中的變量中？我想在一個變量中存儲一個以后使用的命令(不是命令的輸出，而是命令本身)。我有一個簡單的腳本如下：command="ls";echo "Command: $command"; #Output is: Command: lsb=`$command`;echo $b; #Output is:
public_html REV test... (command worked successfully)然而，當我嘗試一些更復雜的東西時，它就失敗了。例如，如果我command="ls | grep -c '^'";產出如下：Command: ls | grep -c '^'ls: cannot access |: No such file or directory
ls: cannot access grep: No such file or directory
ls: cannot access '^': No such file or directory知道我如何將這樣的命令(使用管道/多個命令)存儲在變量中以供以后使用嗎？
3 回答
慕工程0101907
TA貢獻1887條經驗 獲得超5個贊
var=$(echo "asdf")echo $var# => asdf
stored_date=$(date)echo $stored_date# => Thu Jan 15 10:57:16 EST 2015# (wait a few seconds)echo $stored_date# => Thu Jan 15 10:57:16 EST 2015
stored_date=`date`echo $stored_date# => Thu Jan 15 11:02:19 EST 2015# (wait a few seconds)echo $stored_date# => Thu Jan 15 11:02:19 EST 2015
$(...)
stored_date=$(eval "date")echo $stored_date# => Thu Jan 15 11:05:30 EST 2015# (wait a few seconds)echo $stored_date# => Thu Jan 15 11:05:30 EST 2015
eval
stored_date="date" # < storing the command itselfecho $(eval "$stored_date")# => Thu Jan 15 11:07:05 EST 2015# (wait a few seconds)echo $(eval "$stored_date")# => Thu Jan 15 11:07:16 EST 2015# ^^ Time changed
stored_date="date -u"# ...
eval
添加回答
舉報
0/150
提交
取消