View source for Search in paragraph's text

{{draft task}}

The goal is to verify the presence of a word or regular expression within several paragraphs of text (structured or not) and to print the relevant paragraphs on the standard output.

So here, let’s imagine that we are trying to verify the presence of a keyword "SystemError" within the paragraphs "Traceback (most recent call last):" in the file Traceback.txt

<pre>
cat Traceback.txt :

2018-06-19 23:19:34,877 ERROR Processes plugin raised an exception.
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/landscape/sysinfo/sysinfo.py", line 99, in run
    result = plugin.run()
  File "/usr/lib/python3/dist-packages/landscape/sysinfo/processes.py", line 18, in run
    for process_info in info.get_all_process_info():
  File "/usr/lib/python3/dist-packages/landscape/lib/process.py", line 39, in get_all_process_info
    process_info = self.get_process_info(process_id)
  File "/usr/lib/python3/dist-packages/landscape/lib/process.py", line 61, in get_process_info
    cmd_line = file.readline()
  File "/usr/lib/python3.6/encodings/ascii.py", line 26, in decode
    return codecs.ascii_decode(input, self.errors)[0]
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc5 in position 152: ordinal not in range(128)

2018-06-19 23:19:34,877 ERROR Processes plugin raised an exception.
Traceback (most recent call last):
    vmodl.fault.SystemError: (vmodl.fault.SystemError) {
    dynamicType = ,
    dynamicProperty = (vmodl.DynamicProperty) [],
    msg = 'A general system error occurred: Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Sysinfo error: Bad parameterSee VMkernel log for details.',
    faultCause = ,
    faultMessage = (vmodl.LocalizableMessage) [],
    reason = 'Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Sysinfo error: Bad parameterSee VMkernel log for details.'
    }

[Tue Jan 21 16:16:19.250245 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] Traceback (most recent call last):
[Tue Jan 21 16:16:19.252221 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] SystemError: unable to access /home/dir
[Tue Jan 21 16:16:19.249067 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] mod_wsgi (pid=6515): Failed to exec Python script file '/home/pi/RaspBerryPiAdhan/www/sysinfo.wsgi'.
[Tue Jan 21 16:16:19.249609 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] mod_wsgi (pid=6515): Exception occurred processing WSGI script '/home/pi/RaspBerryPiAdhan/www/sysinfo.wsgi'.

[Tue Jan 21 17:16:19.250245 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] Traceback (most recent call last):
[Tue Jan 21 17:16:19.250679 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757]   File "/home/pi/RaspBerryPiAdhan/www/sysinfo.wsgi", line 5, in <module>
[Tue Jan 21 17:16:19.251735 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757]     from test import app as application
[Tue Jan 21 17:16:19.252221 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] ImportError: cannot import name app

2021-04-23 17:13:14,425 ERROR    Network plugin raised an exception.
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/landscape/sysinfo/sysinfo.py", line 99, 
in run
    result = plugin.run()
  File "/usr/lib/python3/dist-packages/landscape/sysinfo/network.py", line 36, 
in run
    device_info = self._get_device_info()
  File "/usr/lib/python3/dist-packages/landscape/lib/network.py", line 163, in 
get_active_device_info
    speed, duplex = get_network_interface_speed(
  File "/usr/lib/python3/dist-packages/landscape/lib/network.py", line 249, in 
get_network_interface_speed
    res = status_cmd.tostring()
AttributeError: 'array.array' object has no attribute 'tostring'

11/01 18:24:57.726 ERROR| log:0072| post-test sysinfo error: 11/01 18:24:57.727 ERROR| traceback:0013| Traceback (most recent call last): 11/01 18:24:57.728 ERROR| traceback:0013| File "/tmp/sysinfo/autoserv-0tMj3m/common_lib/log.py", line 70, in decorated_func 11/01 18:24:57.729 ERROR| traceback:0013| fn(*args, **dargs) 11/01 18:24:57.730 ERROR| traceback:0013| File "/tmp/sysinfo/autoserv-0tMj3m/bin/base_sysinfo.py", line 286, in log_after_each_test 11/01 18:24:57.731 ERROR| traceback:0013| old_packages = set(self._installed_packages) 11/01 18:24:57.731 ERROR| traceback:0013| TypeError: 'NoneType' object is not iterable

12/01 19:24:57.726 ERROR| log:0072| post-test sysinfo error: 11/01 18:24:57.727 ERROR| traceback:0013| Traceback (most recent call last): 11/01 18:24:57.728 ERROR| traceback:0013| File "/tmp/sysinfo/autoserv-0tMj3m/common_lib/log.py", line 70, in decorated_func 11/01 18:24:57.729 ERROR| traceback:0013| fn(*args, **dargs) 11/01 18:24:57.730 ERROR| traceback:0013| File "/tmp/sysinfo/autoserv-0tMj3m/bin/base_sysinfo.py", line 286, in log_after_each_test 11/01 18:24:57.731 ERROR| traceback:0013| old_packages = set(self._installed_packages) 11/01 18:24:57.731 ERROR| traceback:0013| SystemError: no such file or directory

Traceback (most recent call last):
    File "/usr/lib/vmware-vpx/vsan-health/pyMoVsan/VsanClusterPrototypeImpl.py", line 1492, in WaitForUpdateTask
    WaitForTask(task)
    File "/usr/lib/vmware-vpx/pyJack/pyVim/task.py", line 123, in WaitForTask
    raise task.info.error
    vmodl.fault.SystemError: (vmodl.fault.SystemError) {
    dynamicType = ,
    dynamicProperty = (vmodl.DynamicProperty) [],
    msg = 'A general system error occurred: Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Sysinfo error: Bad parameterSee VMkernel log for details.',
    faultCause = ,
    faultMessage = (vmodl.LocalizableMessage) [],
    reason = 'Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Sysinfo error: Bad parameterSee VMkernel log for details.'
    }
</pre>

The expected result must be (with ---------------- for paragraphs matched's sep) :

<pre>
Traceback (most recent call last):
    vmodl.fault.SystemError: (vmodl.fault.SystemError) {
    dynamicType = ,
    dynamicProperty = (vmodl.DynamicProperty) [],
    msg = 'A general system error occurred: Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Sysinfo error: Bad parameterSee VMkernel log for details.',
    faultCause = ,
    faultMessage = (vmodl.LocalizableMessage) [],
    reason = 'Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Sysinfo error: Bad parameterSee VMkernel log for details.'
    }
----------------
Traceback (most recent call last):
[Tue Jan 21 16:16:19.252221 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] SystemError: unable to access /home/dir
[Tue Jan 21 16:16:19.249067 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] mod_wsgi (pid=6515): Failed to exec Python script file '/home/pi/RaspBerryPiAdhan/www/sysinfo.wsgi'.
[Tue Jan 21 16:16:19.249609 2020] [wsgi:error] [pid 6515:tid 3041002528] [remote 10.0.0.12:50757] mod_wsgi (pid=6515): Exception occurred processing WSGI script '/home/pi/RaspBerryPiAdhan/www/sysinfo.wsgi'.
----------------
Traceback (most recent call last): 11/01 18:24:57.728 ERROR| traceback:0013| File "/tmp/sysinfo/autoserv-0tMj3m/common_lib/log.py", line 70, in decorated_func 11/01 18:24:57.729 ERROR| traceback:0013| fn(*args, **dargs) 11/01 18:24:57.730 ERROR| traceback:0013| File "/tmp/sysinfo/autoserv-0tMj3m/bin/base_sysinfo.py", line 286, in log_after_each_test 11/01 18:24:57.731 ERROR| traceback:0013| old_packages = set(self._installed_packages) 11/01 18:24:57.731 ERROR| traceback:0013| SystemError: no such file or directory
----------------
Traceback (most recent call last):
    File "/usr/lib/vmware-vpx/vsan-health/pyMoVsan/VsanClusterPrototypeImpl.py", line 1492, in WaitForUpdateTask
    WaitForTask(task)
    File "/usr/lib/vmware-vpx/pyJack/pyVim/task.py", line 123, in WaitForTask
    raise task.info.error
    vmodl.fault.SystemError: (vmodl.fault.SystemError) {
    dynamicType = ,
    dynamicProperty = (vmodl.DynamicProperty) [],
    msg = 'A general system error occurred: Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Sysinfo error: Bad parameterSee VMkernel log for details.',
    faultCause = ,
    faultMessage = (vmodl.LocalizableMessage) [],
    reason = 'Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.: Sysinfo error: Bad parameterSee VMkernel log for details.'
    }
----------------
</pre>

=={{header|Awk}}==
Using the awk "Record Separator" :
<lang awk>
 awk -v ORS='\n\n'                 '/SystemError/ { print RS $0 }' RS="Traceback" Traceback.txt |\
 awk -v ORS='\n----------------\n' '/Traceback/'                   RS="\n\n"
</lang>
Note : 1st awk is used to search for an expression (regular or not) within paragraphs, and 2nd awk is used for formatting


=={{header|Raku}}==
Just use the same technique as already thoroughly explored in tasks [[Retrieve_and_search_chat_history#Raku|Retrieve and search chat history]] and [[XXXX_redacted#Raku|XXXX redacted]] among many others.
<lang perl6>.say if $paragraph.contains: 'whatever';</lang>