bash 变量来存储目录名和空格

Question

我正在编写一个 bash 脚本来收集一些目录（满足条件）和rsync 那些到远程位置。总体而言，脚本如下所示；

sources=""
for d in /somewhere/* ; do 
  if $d meets condition; then
    sources="$sources $(printf %q "$d")"
  fi
done
if [ ! -z $sources ] ; then 
  rsync -vrz $sources /remote/target/
fi

请注意，我使用printf %q 来转义目录名称中的空格。 但是当目录名中有空格时，比如"/somewhere/dir name"满足条件时，rsync认为是两个目录，运行失败；

(at /home/u/) $ bash script.sh

sending incremental file list
rsync: link_stat "/somewhere/dir\" failed: No such file or directory (2)
rsync: link_stat "/home/u/name" failed: No such file or directory (2)

rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1196) [sender=3.1.2]

如果我只是通过将最后一行更改为来打印 rsync 命令

echo rsync -vrz $sources /remote/target/

看起来还不错。

(at /home/u/) $ bash script.sh
rsync -vrz /somewhere/dirname /somewhere/dir\ name /remote/target

但是使用set -x 会显示一些古怪的事情。

(at /home/u/) $ bash script.sh
+ rsync -vrz /somewhere/dirname '/somewhere/dir\' name /remote/target
sending incremental file list
rsync: link_stat "/somewhere/dir\" failed: No such file or directory (2)
rsync: link_stat "/home/u/name" failed: No such file or directory (2)

rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1196) [sender=3.1.2]

我也尝试使用双引号目录名称而不是 printf %q，但它也不起作用，原因略有不同。

(at /home/u/) $ bash script.sh
+ rsync -vrz '"/somewhere/dirname"' '"/somewhere/dir' 'name"' /remote/target
sending incremental file list
rsync: change_dir "/home/u//"/somewhere" failed: No such file or directory (2)
rsync: change_dir "/home/u//"/somewhere" failed: No such file or directory (2)
rsync: link_stat "/home/u/name"" failed: No such file or directory (2)

sent 20 bytes  received 12 bytes  64.00 bytes/sec
total size is 0  speedup is 0.00
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1196) [sender=3.1.2]

一些参数周围的单引号是从哪里来的？在单行变量中收集带有空格的目录以用作cp、mv 或rsync 中的源的最佳方法是什么？

Answer 1

改为使用数组。

sources=()
for d in /somewhere/* ; do 
  if $d meets condition; then
    sources+=("$d")
  fi
done
if [ "${sources[*]}" ]; then 
  rsync -vrz "${sources[@]}" /remote/target/
fi

带有set -x 的单引号输出只是为了消除歧义，因此您可以准确地看到实际文字空格的位置（与作为参数分隔符的句法空格相反）。