I am parsing command output and putting results into array.
我正在解析命令输出并将结果放入数组。
Works fine until exiting the inner loop - output array is empty.
工作正常，直到退出内部循环 - 输出数组为空。
declare -a KEYS
#-----------------------------------------------------------------------------#
get_keys()
{
# this extracts key NAMES from log in format "timestamp keycode"
$glue_dir/get_keys $ip | while read line; do
echo line: $line
set -- $line # $1 timestamp $2 keycode
echo 1: $1 2: $2
key=(`egrep "\\s$2$" "$glue_dir/keycodes"`) # tested for matching '40' against 401, 402 etc
set -- $key # $1 key name $2 keycode
KEYS+=("$1")
echo key $1
echo KEYS inside loop: "${KEYS[@]}"
done
echo KEYS outside loop: "${KEYS[@]}"
}
The output when run agains two output lines:
再次运行两个输出行时的输出：
line: 1270899320451 38
1: 1270899320451 2: 38
key UP
KEYS inside loop: UP
line: 1270899320956 40
1: 1270899320956 2: 40
key DOWN
KEYS inside loop: UP DOWN
KEYS outside loop:
I spent an hour trying to figure this out. Please help. ;-)
我花了一个小时试图解决这个问题。请帮忙。 ;-)
1 个解决方案
#1
21
When you use a pipe (|) to pass your command output to while, your while loop runs in a subshell. When the loop ends, your subshell terminates and your variables will not be available outside your loop.
当您使用管道（|）将命令输出传递给while时，您的while循环在子shell中运行。当循环结束时，您的子shell终止，并且您的变量将不会在循环外可用。
Use process substitution instead:
改为使用流程替换：
while read line; do
# ...
done < <($glue_dir/get_keys $ip)
#1
21
When you use a pipe (|) to pass your command output to while, your while loop runs in a subshell. When the loop ends, your subshell terminates and your variables will not be available outside your loop.
当您使用管道（|）将命令输出传递给while时，您的while循环在子shell中运行。当循环结束时，您的子shell终止，并且您的变量将不会在循环外可用。
Use process substitution instead:
改为使用流程替换：
while read line; do
# ...
done < <($glue_dir/get_keys $ip)