为什么这个Shell结果不是我想要的结果

dirtysalt

#!/bin/bash
directory="."
sum=0
ls "$directory" | more |
while read file
do
    file="$directory"/"$file"
    if [ -f "$file" ]
    then
        set -- `ls -l "$file"`
        sum=`expr $sum + $4`
    fi
done
echo "the size of all ordinary files in $directory is $sum bytes"
为什么最终结果sum总是0，但是在进行调试模式下#！/bin/bash -x，sum每次都在变化

luo118

不知道你想要的结果是点样,但是我觉得 这两步是有点问题,
      set -- `ls -l "$file"`  这是什么意思,不是很明白,set --
        sum=`expr $sum + $4`

$4 未定义, 是否来处系统变量设定在,
sum=`expr $sum + $4` 是不是应该改为 sum=$[$sum+4] ;echo $sum
因为不知道你想要的结果,只能给你这些提示了,
在调试模下,你应看到expr 0+ 的错误,

ailms

lz 的脚本有不少的问题

dirtysalt

set -- `ls -l "$file"`
--不解析ls -l file产生结果最前面的－，因为ls -l对于普通文件会产生－rwx....,这样set解析就不会正确

$4的字段表示文件的大小
我的程序目的是取得当前目录下所有文件的大小。没错有现成的命令可用，但是我想知道这么脚本在哪个地方错误，这是我修改后的结果，我感觉在shell里面是不是也有作用域问题。还有我的系统是unix-center的fedora系统，shell bash3.1

程序是
#!/bin/bash
directory="."
sum=0
ls "$directory" | more |
while read file
do
        file="$directory"/"$file"
        if [ -f "$file" ]
        then
                set -- `ls -l "$file"`
                sum=`expr $sum + $4`
                echo "until $file,the size is $sum"
        fi
done
echo "the size of all ordinary files in $directory is $sum bytes"


结果是
until ./addall,the size is 13739
until ./all_user,the size is 27478
until ./ar_test.a,the size is 41217
until ./ar_test.c,the size is 54956
until ./ar_test.o,the size is 68695
until ./a.txt,the size is 82434
until ./caller,the size is 96173
until ./caller.c,the size is 109912
until ./case_demo,the size is 123651
until ./catargs_demo,the size is 137390
until ./dext,the size is 151129
until ./diff2,the size is 164868
until ./display_name,the size is 178607
until ./error.log,the size is 192346
until ./file1,the size is 206085
until ./file3,the size is 219824
until ./file4,the size is 233563
until ./for_demo1,the size is 247302
until ./fs,the size is 261041
until ./fs_demo,the size is 274780
until ./if_demo,the size is 288519
until ./read_demo,the size is 302258
until ./sample,the size is 315997
until ./shift_demo,the size is 329736
until ./student_address,the size is 343475
until ./student_address_bak,the size is 357214
until ./student_address_bak2,the size is 370953
until ./swap_macro,the size is 384692
until ./swap_macro.c,the size is 398431
until ./swap_macro.c~,the size is 412170
until ./trap_demo,the size is 425909
until ./until_demo,the size is 439648
until ./user_info,the size is 453387
until ./while_demo,the size is 467126
until ./words_from_celebrity_in_unix.txt,the size is 480865
the size of all ordinary files in . is 0 bytes

ailms

1. 
   
2. sum=`expr $sum + $4`
   

复制代码

把 + 改为 '+' 看看

寂寞烈火

1. 
   
2. for file in *;do [[ -f $file ]] && ((sum+=$(stat -c %s $file)));done ;echo $sum

复制代码

dirtysalt

通过管道产生的结果会产生错误
#!/bin/bash
sum=0
ls . | more |
while read a
do
        [[ -f $a ]] && ((sum+=$(stat -c %s $a)))
done
echo $sum

可以工作的程序
#!/bin/sh
directory="."
sum=0
for file in "$directory"/*
do
        if [ -f $file ]
        then
                set -- `ls -l $file`
                sum=`expr $sum + $4`
                echo "until $file,the size is $sum"
        fi
done
echo $sum
echo "the size of all ordinary files in $directory is $sum bytes"

但是为什么这样会错呢？？

[ 本帖最后由 dirtysalt 于 2007-10-25 23:50 编辑 ]