Shell output redirection inside a function

问题

function grabSourceFile
{
    cd /tmp/lmpsource
    wget $1 >  $LOG
    baseName=$(basename $1)
    tar -xvf $baseName > $LOG
    cd $baseName
}

When I call this function The captured output is not going to the log file. The output redirection works fine until I call the function. The $LOG variable is set at the top of the file. I tried echoing statements and they would not print. I am guessing the function captures the output itself? If so how do push the output to the file instead of the console. (The wget above prints to console, while an echo inside the function does nothing.)

回答1:

As mentioned earlier, you are writing to the same logfile twice. Your function is logging the output of 'wget' and is then overwriting that output later on, with the tar command.

Myself, I like to log outside of functions. This will reduce the chance that your logfile gets clobbered. It also keeps the function code neat and tidy.

function grabSourceFile
{
        cd /tmp/lmpsource
        wget $1
        baseName=$(basename $1)
        tar -xvf $baseName
        cd $baseName
} >> $LOG

Or just do:

grabSourceFile >> $LOG

回答2:

Redirection works the same inside and outside of functions.

Your problem is likely that you want a double greater than sign rather than a single greater than sign. I.e. wget $1 >> $LOG. The redirection on your tar command truncates the output from wget.

回答3:

I found the problem. It was with wget. wget has an option specifically for logging as I guess it can't have it's output redirected using the > (something with curses.) My working function ended up being:

function grabSourceFile
{
        cd /tmp/lmpsource
        wget -a /tmp/lamps_install.log $1
        baseName=$(basename $1)
        tar -xvf $baseName >> $LOG
        cd $baseName
}

来源：https://stackoverflow.com/questions/2952809/shell-output-redirection-inside-a-function

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Linux

bash

function

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