为什么我在 bash 字符串相等性测试中遇到意外的运算符错误？
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Why am i getting an unexpected operator error in bash string equality test?
提问by John Hall
Where is the error on line four?
第四行的错误在哪里？
if [ $bn == README ]; then
which i still get if i write it as
如果我把它写成，我仍然会得到
if [ $bn == README ]
then
or
或者
if [ "$bn" == "README" ]; then
Context:
语境：
for fi in /etc/uwsgi/apps-available/*
do
bn=`basename $fi .ini`
if [ $bn == "README" ]
then
echo "~ ***#*** ~"
else
echo "## Shortend for convience ##"
fi
done
回答by konsolebox
You can't use == for single bracket comparisons ([ ]). Use single = instead. Also you must quote the variables to prevent expansion.
不能将 == 用于单括号比较 ([ ])。使用单个 = 代替。此外，您必须引用变量以防止扩展。
if [ "$bn" = README ]; then
If you use [[ ]], that could apply and you wouldn't need to quote the first argument:
如果您使用 [[ ]]，那可能适用并且您不需要引用第一个参数：
if [[ $bn == README ]]; then
回答by Christopher Neylan
Add the following to the top of your script:
将以下内容添加到脚本的顶部：
#! /bin/bash
In bash, ==is the sameas =when used inside of single brackets. This is, however, not portable. So you should explicitly tell the shell to use bash as the script's interpreter by putting #! /bin/bashat the top of the script.
在bash中，==相同的=单一支架内使用时。然而，这不是便携式的。因此，您应该通过放置#! /bin/bash在脚本的顶部来明确告诉 shell 使用 bash 作为脚本的解释器。
Alternatively, do your string comparisons using =. Note that the ==operator behaves differentlywhen used inside of double-brackets than when inside of single-brackets (see the link).
或者，使用=. 请注意，==运算符在双括号内使用时的行为与在单括号内使用时的行为不同（请参阅链接）。
