英文:
I am writing a SH Shell script in Linux RedHat. Can I use "set -x | tee > output.file"?
问题
在我的脚本开头，我有一行 "set -x"。这当然会将所有输出发送到屏幕上。这正是我喜欢的，这样我可以看到脚本正在做什么并解决问题。一旦脚本正确工作，我会注释掉 "set -x" 这一行。
我想将 "set -x" 的输出保存到一个文件中，而不是仅在屏幕上显示。有没有办法做到这一点？
我尝试过 "set -x | tee ScriptNameHere.DEBUG"，但它给我生成了一个名为 ScriptNameHere.DEBUG 的零字节文件...一个空文件。
"set -x | tee scriptname.debug"
"set -x | tee -a scriptname.debug"
都会生成一个名为 scriptname.debug 的零字节文件。
英文:
At the beginning of my script I have the "set -x" line. This, of course, sends all output to the screen. This is exactly what I like so that I can see what the script is doing and fix issues along the way. Once the script works correctly I comment out the "set -x" line.
I would like to tee the output of set -x so that I have a file to look at instead of using the display only. Is there a way to do this?
I've tried "set -x | tee ScriptNameHere.DEBUG" and it gives me a file named ScriptNameHere.DEBUG with ZERO bytes in it... an empty file.
set -x | tee scriptname.debug
set -x | tee -a scriptname.debug
All give me a Zero byte file named scriptname.debug.
答案1
得分: 5
你不能使用sh来实现这个，但你可以使用bash（只要你不在苹果提供的古老版本上）。
#!/usr/bin/env bash
case $BASH_VERSION in
''|[1-3].*|4.[012].*) echo "错误：需要bash 4.3或更新版本" >&2; exit 1;;
esac
exec {BASH_XTRACEFD}> >(tee -a ScriptNameHere.DEBUG >&2)
set -x
# ... 你的脚本其他内容在下面
解释上述内容：
- 当
exec只传递重定向，而不是命令时，它在当前shell中执行这些重定向。 - 在bash 4.x及更高版本中，
BASH_XTRACEFD给出了xtrace (set -x)将写入日志的文件描述符号。 - 从4.x系列的某个版本开始（4.1？4.3？），
{varname}>file的重定向动态地为变量"$varname"分配一个写入文件file的文件描述符号。 >(...)是一个进程替代，被替换为一个文件名（通常在Linux上类似于/dev/fd/##或/proc/self/fd/##），当写入时，它将向由命令...调用的程序传递内容；一个用于读取的变种是<(...)
因此，净效果是在后台启动一个tee的副本并将其附加到一个文件描述符号，该文件描述符号的编号写入了$BASH_XTRACEFD，因此当稍后运行set -x时，日志将被写入该tee的副本，然后写入指定的文件。
英文:
You can't do this with sh, but you can do it with bash (as long as you aren't on the ancient version shipped by Apple).
#!/usr/bin/env bash
case $BASH_VERSION in
''|[1-3].*|4.[012].*) echo "ERROR: bash 4.3 or newer required" >&2; exit 1;;
esac
exec {BASH_XTRACEFD}> >(tee -a ScriptNameHere.DEBUG >&2)
set -x
# ... other content of your script below
Explaining the above:
- When
execis passed only redirections, and not a command, it performs those redirections in the current shell. - In bash 4.x and later,
BASH_XTRACEFDgives the number of the file descriptor where xtrace (set -x) will write logs. - Starting somewhere later in the 4.x series (4.1? 4.3?), a redirection of
{varname}>filedynamically assigns a file descriptor number to the variable"$varname"of a handle writing to filefile. >(...)is a process substitution, replaced with a filename (typically on Linux something like/dev/fd/##or/proc/self/fd/##) that, when written to, will deliver content to the program invoked by the command...; one for read is instead<(...).
Thus, the net effect is to start a copy of tee in the background and attach it to a file descriptor whose number is written to $BASH_XTRACEFD, such that when set -x is later run, the logs will be written to that copy of tee and thereafter to the specified file.
答案2
得分: 1
set -x | whatever 或 >wherever 只会发送set -x 本身的输出 - set -x 并不输出任何东西！它是用来 开启 跟踪输出的，这些输出来自于shell，而不是shell运行的任何命令。
你可以通过重定向标准错误来捕获它，例如：
exec 2>>trace.out
set -x
或者，如果要将它同时发送到屏幕和文件，可以使用以下命令：
exec 2> >(tee -a trace.out)
set -x
英文:
set -x | whatever or >wherever just sends the output of the set -x itself - which doesn't output anything! It turns on tracing output, which comes from the shell, not any of the commands the shell runs.
You can capture it, though; just by redirecting stderr, e.g. with
exec 2>>trace.out
set -x
or, to have it go to both the screen and the file
exec 2> >(tee -a trace.out)
set -x
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