如何使用bash脚本选择部分txt文件？

Question

我有一个logcat.txt文件，我只能从其中选择一些字段。我试着用我的具体案例来更好地解释它：

file.txt

I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412946569,"result":"","class":"android.os.SystemProperties","method":"get","type":"content","args":["debug.second-display.pkg"]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412946637,"result":"","class":"android.os.SystemProperties","method":"get","type":"content","args":["gsm.sim.operator.iso-country"]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412946637,"result":"","class":"android.telephony.TelephonyManager","method":"getSimCountryIso","type":"fingerprint","args":[]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412949364,"result":"","class":"android.os.SystemProperties","method":"get","type":"content","args":["gsm.sim.operator.iso-country"]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412949364,"result":"","class":"android.telephony.TelephonyManager","method":"getSimCountryIso","type":"fingerprint","args":[]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412949365,"class":"android.app.ContextImpl","method":"registerReceiver","type":"binder","args":["horoscope.android.LicenseActivity$3@52828f54",{"mPriority":0,"mActions":["SMS_SENT"],"mHasPartialTypes":false}]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412949373,"class":"android.app.ContextImpl","method":"registerReceiver","type":"binder","args":["horoscope.android.LicenseActivity$3@52828f54",{"mPriority":0,"mActions":["SMS_SENT"],"mHasPartialTypes":false}]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412949380,"class":"android.app.ContextImpl","method":"registerReceiver","type":"binder","args":["horoscope.android.LicenseActivity$4@52931658",{"mPriority":0,"mActions":["SMS_DELIVERED"],"mHasPartialTypes":false}]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412949384,"class":"android.app.ContextImpl","method":"registerReceiver","type":"binder","args":["horoscope.android.LicenseActivity$4@52931658",{"mPriority":0,"mActions":["SMS_DELIVERED"],"mHasPartialTypes":false}]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412949404,"class":"javax.crypto.spec.SecretKeySpec","method":"javax.crypto.spec.SecretKeySpec","type":"crypto","args":["\n0x00000000 0A F9 E4 5D BB DB CE 8B 57 27 4D 5A 1C 2A 37 7D ...]....W'MZ.*7}","AES"]}
I/Xposed  ( 2559): Droidmon-apimonitor-com.astrolog.great.little.war.game.free:{"timestamp":1463412949404,"class":"javax.crypto.spec.SecretKeySpec","method":"javax.crypto.spec.SecretKeySpec","type":"crypto","args":["\n0x00000000 0A F9 E4 5D BB DB CE 8B 57 27 4D 5A 1C 2A 37 7D ...]....W'MZ.*7}","AES"]}

因此，我必须从这个文件中为每一行只选择"class":"“、”方法“：”“。结果必须是这样的：

{"class":"android.os.SystemProperties","method":"get"}

{"class":"android.os.SystemProperties","method":"get"} {"class":"android.telephony.TelephonyManager","method":"getSimCountryIso"} {"class":"android.os.SystemProperties","method":"get"} {"class":"android.telephony.TelephonyManager","method":"getSimCountryIso"} {"class":"javax.crypto.spec.SecretKeySpec","method":"javax.crypto.spec.SecretKeySpec"} {"class":"javax.crypto.spec.SecretKeySpec","method":"javax.crypto.spec.SecretKeySpec"}

我试着用sed命令来做这件事，但我做不到。

Answer 1

这个怎么样：

sed 's/.*\("class":"[a-zA-Z\.]*","method":"[a-zA-Z\.]*"\).*/\{\1\}/' logcat.txt

这基本上是基于一个大的捕获组的匹配。我假设类字段和方法字段只包含alpha字符和'.‘。你可能得调整一下。

Answer 2

您可以尝试使用sed：

sed 's/^.*"class":"([^"]*)".*"method":"([^"]*)".*$/{"class":"\1","method":"\2"}/gp' file.txt -nr

Answer 3

在bash中直接解析JSON将很困难，使用sed可能很难维护(如果您想扩展结果集，或者JSON键排序是动态的)。

但是，如果您不反对使用内联python，这可以在一行中完成：

cut -d: -f3- file.txt | while read line; do \
    echo $line |\
    python -c "import sys, json; obj = json.load(sys.stdin); trimmed = {'class': obj['class'], 'method': obj['method']}; print(json.dumps(trimmed));"; \
done

它也不是最友好的解决方案，但它将只使用file.txt的JSON部分，将其逐行传递给python代码，该代码将选择并输出您感兴趣的部分。

要扩展输出，只需向python脚本中的部分添加更多内容。