在 Linux 上,我可以运行一个命令并在另一个命令中立即使用其结果:
go test $(glide novendor)
上述命令将首先评估glide novendor
然后将结果代入。例如,如果运行glide novendor
返回./stuff/
,则外部命令将被调用go test ./stuff/
。
Windows 中运行这样的嵌套命令的等效版本是什么?
答案1
go test $(glide novendor)
上述命令将首先评估 glide novendor,然后代入结果。例如,如果运行 glide novendor 返回 ./stuff/,则外部命令将被调用为 go test ./stuff/。
Windows 中运行这样的嵌套命令的等效版本是什么?
对于您标记的 Windows 命令行方式,请尝试一下。只需将一个命令的结果作为传递的参数迭代到另一个命令即可。
FOR /F %A IN ('glide novendor') DO go test %~A
。
现在glide
,go
我认为必须是有效的 Windows 命令才能执行此操作,并确保在必要时检查环境变量。
进一步的研究
类型FOR /?
从 Windows 命令提示符中按Enter
FOR /F ["options"] %variable IN (file-set) DO command [command-parameters]
FOR /F ["options"] %variable IN ("string") DO command [command-parameters]
FOR /F ["options"] %variable IN ('command') DO command [command-parameters]
or, if usebackq option present:
FOR /F ["options"] %variable IN (file-set) DO command [command-parameters]
FOR /F ["options"] %variable IN ('string') DO command [command-parameters]
FOR /F ["options"] %variable IN (`command`) DO command [command-parameters]
filenameset is one or more file names. Each file is opened, read
and processed before going on to the next file in filenameset.
Processing consists of reading in the file, breaking it up into
individual lines of text and then parsing each line into zero or
more tokens. The body of the for loop is then called with the
variable value(s) set to the found token string(s). By default, /F
passes the first blank separated token from each line of each file.
Blank lines are skipped. You can override the default parsing
behavior by specifying the optional "options" parameter. This
is a quoted string which contains one or more keywords to specify
different parsing options. The keywords are:
eol=c - specifies an end of line comment character
(just one)
skip=n - specifies the number of lines to skip at the
beginning of the file.
delims=xxx - specifies a delimiter set. This replaces the
default delimiter set of space and tab.
tokens=x,y,m-n - specifies which tokens from each line are to
be passed to the for body for each iteration.
This will cause additional variable names to
be allocated. The m-n form is a range,
specifying the mth through the nth tokens. If
the last character in the tokens= string is an
asterisk, then an additional variable is
allocated and receives the remaining text on
the line after the last token parsed.
usebackq - specifies that the new semantics are in force,
where a back quoted string is executed as a
command and a single quoted string is a
literal string command and allows the use of
double quotes to quote file names in
filenameset.
Some examples might help:
FOR /F "eol=; tokens=2,3* delims=, " %i in (myfile.txt) do @echo %i %j %k
would parse each line in myfile.txt, ignoring lines that begin with
a semicolon, passing the 2nd and 3rd token from each line to the for
body, with tokens delimited by commas and/or spaces. Notice the for
body statements reference %i to get the 2nd token, %j to get the
3rd token, and %k to get all remaining tokens after the 3rd. For
file names that contain spaces, you need to quote the filenames with
double quotes. In order to use double quotes in this manner, you also
need to use the usebackq option, otherwise the double quotes will be
interpreted as defining a literal string to parse.
%i is explicitly declared in the for statement and the %j and %k
are implicitly declared via the tokens= option. You can specify up
to 26 tokens via the tokens= line, provided it does not cause an
attempt to declare a variable higher than the letter 'z' or 'Z'.
Remember, FOR variables are single-letter, case sensitive, global,
and you can't have more than 52 total active at any one time.
You can also use the FOR /F parsing logic on an immediate string, by
making the filenameset between the parenthesis a quoted string,
using single quote characters. It will be treated as a single line
of input from a file and parsed.
Finally, you can use the FOR /F command to parse the output of a
command. You do this by making the filenameset between the
parenthesis a back quoted string. It will be treated as a command
line, which is passed to a child CMD.EXE and the output is captured
into memory and parsed as if it was a file. So the following
example:
FOR /F "usebackq delims==" %i IN (`set`) DO @echo %i
would enumerate the environment variable names in the current
environment.
In addition, substitution of FOR variable references has been enhanced.
You can now use the following optional syntax:
%~I - expands %I removing any surrounding quotes (")
%~fI - expands %I to a fully qualified path name
%~dI - expands %I to a drive letter only
%~pI - expands %I to a path only
%~nI - expands %I to a file name only
%~xI - expands %I to a file extension only
%~sI - expanded path contains short names only
%~aI - expands %I to file attributes of file
%~tI - expands %I to date/time of file
%~zI - expands %I to size of file
%~$PATH:I - searches the directories listed in the PATH
environment variable and expands %I to the
fully qualified name of the first one found.
If the environment variable name is not
defined or the file is not found by the
search, then this modifier expands to the
empty string
The modifiers can be combined to get compound results:
%~dpI - expands %I to a drive letter and path only
%~nxI - expands %I to a file name and extension only
%~fsI - expands %I to a full path name with short names only
%~dp$PATH:I - searches the directories listed in the PATH
environment variable for %I and expands to the
drive letter and path of the first one found.
%~ftzaI - expands %I to a DIR like output line
In the above examples %I and PATH can be replaced by other valid
values. The %~ syntax is terminated by a valid FOR variable name.
Picking upper case variable names like %I makes it more readable and
avoids confusion with the modifiers, which are not case sensitive.
答案2
你的命令可能(有点)相当于glide novendor | xargs go test
您也可以尝试python
,或bash
(使用 cygwin 或 mingw)。
答案3
对于任何试图编写批处理脚本以在 CMD 中运行的人。您需要稍微更改语法。您可以在“.bat 文件中像这样编写它
其中 A 是括号内命令的结果。
FOR /F %%A IN ('glide novendor') DO go test %%A