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androidlinuxshelladblogcat

running logcat in background from adb

i'm trying send a command through adb to an android device in order to trigger logcat recording to a file on the device. to do so, i trigger the command:

adb shell "logcat > /sdcard/logcat.log"

so far so good, but the thing is that i need the command to run in the background, and not to keep an open connection to the PC. meaning, that if i send a command and disconnect the usb cable, i want to have the logcat recording keep running in the background. if i execute

$ adb shell

$ logcat > /sdcard/logcat.log &

I can safely disconnect the USB cable, and the recording will keep on going. however, if i execute the command from outside of the shell as follows:

adb shell "logcat > /sdcard/logcat.log &"

i get a file in /sdcard called logcat.log which weights 0 bytes. after trying several varieations i tried placing a script file with the command "logcat > /sdcard/logcat.log &" in /sdcard called /logcatScript.log and running it from outside of the shell using

adb shell "sh /sdcard/logcatScript.log"

but the same 0 byte file is being created.

The device is not rooted, and should not be, so busyBox is not an option.

Solution

  • The best way to solve it is to create a bash script an push it into data/local/tmp folder, on most android devices there is no need to define the #!/system/bin/sh or #!/bin/bash in the first line. The procedure is:

    1)Create file with : logcat > /sdcard/logcat.txt &

    2)adb push /data/local/tmp

    3)adb shell chmod +x /data/local/tmp/

    4)adb shell /data/local/tmp/

    Regards