linux - 使用 cat 输出运行 bash 脚本的问题（额外引号）

Question

我的 apache 目录中有一个bash脚本，可以下载一些图片并对其进行优化。

我的脚本路径在：/var/www/site/storage/optimazer/photo_optimazer.sh

该脚本从txt文件中获取一些命令并将其传递给wget

#!/usr/bin/env bash
..
THREAD="$(cat ${THREAD_FILE})";
$(command -v wget) $THREAD
...

内容${THREAD_FILE}：

$ cat "${THREAD_FILE}"
--user-agent="Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:90.0) Gecko/20100101 Firefox/90.0" -np -r -l 1 -A "jpg" --ignore-case -P /var/www/optimazer/public/optimazed -x http://example.com

我尝试用另一个创建的 bash 来执行这个 bash/usr/local/bin/optimaze.sh

我不得不这样做，因为它将与系统服务一起运行。

这是/usr/local/bin/optimaze.sh内容

#!/usr/bin/env bash

cd /var/www/site/storage/optimazer/
$(command -v bash) photo_optimazer.sh

现在，当我执行optimaze.sh它时，在我的内容中添加一些额外的引号${THREAD}并破坏了脚本，我得到了一些像这样的错误：

--2021-07-30 12:56:59--  http://(windows/
Resolving (windows ((windows)... failed: Name or service not known.
wget: unable to resolve host address ‘(windows’
--2021-07-30 12:56:59--  http://nt/
Resolving nt (nt)... failed: Name or service not known.
wget: unable to resolve host address ‘nt’
--2021-07-30 12:56:59--  http://10.0;/
Resolving 10.0; (10.0;)... failed: Name or service not known.
wget: unable to resolve host address ‘10.0;’
--2021-07-30 12:56:59--  http://win64;/
Resolving win64; (win64;)... failed: Name or service not known.
wget: unable to resolve host address ‘win64;’
--2021-07-30 12:56:59--  http://x64;/
Resolving x64; (x64;)... failed: Name or service not known.
wget: unable to resolve host address ‘x64;’
--2021-07-30 12:56:59--  ftp://rv/90.0)
           => ‘/var/www/scraper/public/***/3/rv/.listing’
Resolving rv (rv)... failed: Name or service not known.
wget: unable to resolve host address ‘rv’
--2021-07-30 12:56:59--  http://gecko/20100101
Resolving gecko (gecko)... failed: Name or service not known.
wget: unable to resolve host address ‘gecko’
--2021-07-30 12:56:59--  http://firefox/90.0%22
Resolving firefox (firefox)... failed: Name or service not known.
wget: unable to resolve host address ‘firefox’

我尝试set -ex在 photo_optimizer.sh 中查看发生了什么

 wget '--user-agent="Mozilla/5.0' '(Windows' NT '10.0;' 'Win64;' 'x64;' 'rv:90.0)' Gecko/20100101 'Firefox/90.0"' -np -A '"jpg,png"' --ignore-case --ignore-length -P /example/path -x http://example.com

它在我的输出中添加了单引号，我${THREAD}不知道为什么！

我用GNU bash, version 4.2.46(2)-release (x86_64-redhat-linux-gnu)

标签： linuxbashshellunixcentos

Answer 1

对于这种特殊情况，一个想法是将每一行提供给xargs.

对于示例数据，我将 OP 加倍$THREAD_FILE：

$ cat tfile
--user-agent="Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:90.0) Gecko/20100101 Firefox/90.0" -np -r -l 1 -A "jpg" --ignore-case -P /var/www/optimazer/public/optimazed -x http://example.com
--user-agent="Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:90.0) Gecko/20100101 Firefox/90.0" -np -r -l 1 -A "jpg" --ignore-case -P /var/www/optimazer/public/optimazed -x http://example.com

第一次通过xargs：

cat tfile | xargs -r wget

cat或者我们可以通过将文件直接提供给以下方式来消除不必要的xargs：

xargs -r -a tfile wget

A few variations on KamilCuk's comment/suggestion:

xargs -r < tfile wget
xargs -r wget < tfile
< tfile xargs -r wget

If we're dealing wih a variable (as with OPs example):

thread=$(head -1 tfile)
xargs -r wget <<< "${thread}"

And expanding on the <<< "${thread}" example ... using this in a loop (eg, need to perform additional processing for each line from a multi-line input file):

while read -r thread
do
    xargs -r wget <<< "${thread}"
done < tfile

All of these generate the following for each line processed:

--2021-07-31 13:50:41--  http://example.com/
Resolving example.com (example.com)... 93.184.216.34, 2606:2800:220:1:248:1893:25c8:1946
Connecting to example.com (example.com)|93.184.216.34|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1256 (1.2K) [text/html]
Saving to: ‘/var/www/optimazer/public/optimazed/example.com/index.html.tmp’

example.com/index.html.tmp               100%[================================================================================>]   1.23K  --.-KB/s    in 0.001s

2021-07-31 13:50:41 (1.25 MB/s) - ‘/var/www/optimazer/public/optimazed/example.com/index.html.tmp’ saved [1256/1256]

Removing /var/www/optimazer/public/optimazed/example.com/index.html.tmp since it should be rejected.