bash 如何在 shell 脚本中检查软件版本？
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How can I check for software versions in a shell script?
提问by CR47
I have two software version checks in my bash script that don't work as I would have expected.
我的 bash 脚本中有两个软件版本检查没有按我预期的那样工作。
DRUSH_VERSION="$(drush --version)"
echo ${DRUSH_VERSION}
if [[ "$DRUSH_VERSION" == "Drush Version"* ]]; then
echo "Drush is installed"
else
echo "Drush is NOT installed"
fi
GIT_VERSION="$(git --version)"
echo ${GIT_VERSION}
if [[ "GIT_VERSION" == "git version"* ]]; then
echo "Git is installed"
else
echo "Git is NOT installed"
fi
Response:
回复：
Drush Version : 6.3.0
Drush is NOT installed
git version 1.8.5.2 (Apple Git-48)
Git is NOT installed
Meanwhile, if I change
同时，如果我改变
DRUSH_VERSION="${drush --version)"
DRUSH_VERSION="${drush --version)"
to
到
DRUSH_VERSION="Drush Version : 6.3.0"
DRUSH_VERSION="Drush 版本：6.3.0"
it responds with
它回应
Drush is installed
Drush 已安装
For now I will use
现在我将使用
if type -p drush;
如果输入 -p drush;
but I would still like to get the version number.
但我还是想得到版本号。
采纳答案by David C. Rankin
There are a couple of issues you can fix. First, if you are not concerned with portability, then you want to use the substring match operator =~instead of ==. That will find git versionwithin git version 1.8.5.2 (Apple Git-48). Second you are missing a $in your [[ "GIT_VERSION" == "git version" ]]test.
您可以解决几个问题。首先，如果您不关心可移植性，那么您想使用子字符串匹配运算符=~而不是==. 那会git version在git version 1.8.5.2 (Apple Git-48). 其次，您$在[[ "GIT_VERSION" == "git version" ]]测试中缺少一个。
So, for example, if you change your tests as follows, you can match substrings. (Note:the =~only works with the [[ ]]operator, and you will need to remove any wildcards *).
因此，例如，如果您按如下方式更改测试，则可以匹配子字符串。（注：在=~只能与[[ ]]经营者，你将需要删除任何通配符*）。
if [[ "$DRUSH_VERSION" =~ "Drush Version" ]]; then
...
if [[ "$GIT_VERSION" =~ "git version" ]]; then
...
Additionally, if you are just checking for the existence of a program and not the specific version number, then you are probably better off using:
此外，如果您只是检查程序是否存在而不是特定版本号，那么您最好使用：
if which $prog_name 2>/dev/null; then...
or using a compound command:
或使用复合命令：
which $prog_name && do something found || do something not found
E.g. for git:
例如git：
if which git 2>/dev/null; then
...
or
或者
which git && echo "git found" || echo "git NOT found"
Note:the redirection of stderrinto /dev/nulljust prevent the error from spewing across the screen in the case that $prog_nameis NOT present on the system.
注：重定向stderr到/dev/null刚刚防止错误在该情况下，在屏幕上喷涌$prog_name不存在系统上。
