Question

我想计算此循环产生的输出数量

cd /System/Library/Extensions
find *.kext -prune -type d | while read d; do
     codesign -v "$d" 2>&1 | grep "invalid signature"
done

如何存储或计算输出？如果尝试使用数组，计数器等，但似乎我无法获得该循环之外的任何内容。

Answer 1

要获得while循环产生的行数，可以使用wc字数

cd /System/Library/Extensions
find *.kext -prune -type d | while read d; do
     codesign -v "$d" 2>&1 | grep "invalid signature"
done | wc -l

wc -l -l选项计算输入中的行数，通过管道输出到while的输出

现在，如果您需要在while循环的每次迭代中计算grep输出的数量，-c的{{1}}选项将非常有用。

grep

cd /System/Library/Extensions find *.kext -prune -type d | while read d; do codesign -v "$d" 2>&1 | grep -c "invalid signature" done抑制正常输出;而是打印匹配行的计数对于每个输入文件

Answer 2

子shell中的经典难点是将变量传回去。

这里有一种获取此信息的方法：

cd /System/Library/Extensions

RESULT=$(find *.kext -prune -type d | {
# we are in a sub-subshell ... 
GCOUNT=0
DIRCOUNT=0
FAILDIR=0
while read d; do
     COUNT=$(codesign -v "$d" 2>&1 | grep -c "invalid signature")
     if [[ -n $COUNT ]]
     then
     if [[ $COUNT > 0 ]]
     then
         echo "[ERROR] $COUNT invalid signature found in $d" >&2
         GCOUNT=$(( $GCOUNT + $COUNT ))
         FAILDIR=$(( $FAILDIR + 1 ))
     fi
     else
     echo "[ERROR] wrong invalid signature count for $d" >&2
     fi
     DIRCOUNT=$(( $DIRCOUNT + 1 ))
done
# this is the actual result, that's why all other output of this subshell are redirected
echo "$DIRCOUNT $FAILDIR $GCOUNT"
})

# parse result integers separated by a space.
if [[ $RESULT =~ ([0-9]+)\ ([0-9]+)\ ([0-9]+) ]]
then
    DIRCOUNT=${BASH_REMATCH[1]}
    FAILDIR=${BASH_REMATCH[2]}
    COUNT=${BASH_REMATCH[3]}
else
    echo "[ERROR] Invalid result format. Please check your script $0" >&2
fi

if [[ -n $COUNT ]]
then
    echo "$COUNT errors found in $FAILDIR/$DIRCOUNT directories"
fi

如何将grep输出存储到循环内的变量中？

2 个答案: