// question

Within Linux process execution records, locate any bash commands where the HISTFILESIZE environment variable was exported. What value was assigned to HISTFILESIZE?

Reference KQL answer and model-by-model comparison.

5cafd6c1-2f43-46eb-ac47-a5301ba0a618
question id
20/23
models correct
1
valid answer
87%
success rate
// reference answer

Human-validated correct answer for this question.

0
// model comparison
ModelAnswerKQL queryStatusTriesTimeCost
gemini-2.5-flash-preview-04-17
0
DeviceProcessEvents
| where FileName == "bash" or ProcessCommandLine contains "bash"
| where ProcessCommandLine contains "export HISTFILESIZE="
| extend HISTFILESIZE_Value = extract(@"export\s+HISTFILESIZE=([^\s]+)", 1, ProcessCommandLine)
| project Timestamp, DeviceName, ProcessCommandLine, HISTFILESIZE_Value
pass212.19s0.0058
gpt-35-turbo
0
DeviceProcessEvents | where ProcessCommandLine contains 'bash' | where ProcessCommandLine contains 'export HISTFILESIZE'
pass13.04s0.0053
gpt-4-turbo-2024-04-09
0
DeviceProcessEvents
| where FileName == 'bash' and ProcessCommandLine has 'export HISTFILESIZE'
| extend HISTFILESIZE_Value = tostring(extract('HISTFILESIZE=(\\d+)',1,ProcessCommandLine))
| project TimeGenerated, DeviceName, AccountName, ProcessCommandLine, HISTFILESIZE_Value
pass321.97s0.1494
gpt-4.1
0
DeviceProcessEvents
| where FileName =~ "bash"
| where ProcessCommandLine has "export HISTFILESIZE="
| extend HISTFILESIZE_Value = extract(@'export HISTFILESIZE=([^\s;]+)', 1, ProcessCommandLine)
| project TimeGenerated, DeviceName, AccountName, ProcessId, ProcessCommandLine, HISTFILESIZE_Value
pass14.37s0.0121
gpt-4.1-finetuned
0
DeviceProcessEvents
| where FolderPath endswith "bash" or ProcessCommandLine contains "/bash "
| where ProcessCommandLine contains "export" and ProcessCommandLine contains "HISTFILESIZE="
pass16.65s0.0227
gpt-4.1-mini
0
DeviceProcessEvents
| where FileName == "bash" // limit to bash processes
| where ProcessCommandLine contains "export HISTFILESIZE=" // commands exporting HISTFILESIZE
| extend HISTFILESIZE_Value = extract(@"export HISTFILESIZE=([^\s]+)", 1, ProcessCommandLine) // extract the assigned value
| project TimeGenerated, DeviceName, AccountName, ProcessCommandLine, HISTFILESIZE_Value
| where isnotempty(HISTFILESIZE_Value)
pass14.06s0.0025
gpt-4.1-nano
0
DeviceProcessEvents
| where ProcessCommandLine contains 'bash'
| where ProcessCommandLine matches regex @'(?i)export\s+HISTFILESIZE\s*=\s*[^\s]+'
| extend HISTFILESIZE_Value=extract(@'HISTFILESIZE\s*=\s*([^\s]+)', 1, ProcessCommandLine)
| project TimeGenerated, DeviceName, ProcessCommandLine, HISTFILESIZE_Value
| where isnotempty(HISTFILESIZE_Value)
pass12.64s0.0006
gpt-4o
0
DeviceProcessEvents
| where InitiatingProcessCommandLine has "export HISTFILESIZE="
| extend HISTFILESIZEValue = extract("HISTFILESIZE=(\\d+)", 1, InitiatingProcessCommandLine)
| project DeviceId, DeviceName, ProcessCommandLine, HISTFILESIZEValue
pass12.41s0.0157
gpt-5-high
0
let LinuxDevices = DeviceInfo
| where OSPlatform =~ "Linux"
| distinct DeviceId;
DeviceProcessEvents
| where ActionType == "ProcessCreated"
| where DeviceId in (LinuxDevices)
| where FileName =~ "bash"
| where isnotempty(ProcessCommandLine)
| where ProcessCommandLine has "export" and ProcessCommandLine has "HISTFILESIZE"
// Extract HISTFILESIZE value (double-quoted, single-quoted, or bare)
| extend HIST_dq = extract(@'(?i)\bHISTFILESIZE\s*=\s*"([^"]+)"', 1, ProcessCommandLine),
         HIST_sq = extract(@'(?i)\bHISTFILESIZE\s*=\s*''([^'']+)''', 1, ProcessCommandLine),
         HIST_bare = extract(@'(?i)\bHISTFILESIZE\s*=\s*([^; \t]+)', 1, ProcessCommandLine)
| extend HISTFILESIZE_Value = coalesce(HIST_dq, HIST_sq, HIST_bare)
| where isnotempty(HISTFILESIZE_Value)
| project TimeGenerated, DeviceName, DeviceId, AccountName, ProcessId, FileName, ProcessCommandLine, HISTFILESIZE_Value
| order by TimeGenerated desc
pass5355.38s0.1899
gpt-5-mini-high
no answer
no query generatedfail50.00s0.0278
gpt-5-mini-low
0
DeviceProcessEvents
| where ProcessCommandLine has "bash"
| where ProcessCommandLine has "HISTFILESIZE"
// extract the value assigned to HISTFILESIZE (case-insensitive), allowing optional quotes
| extend HISTFILESIZE = extract("(?i)HISTFILESIZE\\s*=\\s*['\\\"]?([^'\\\"\\s\\)]+)", 1, ProcessCommandLine)
| extend HISTFILESIZE = iff(isempty(HISTFILESIZE), "(not parsed)", tostring(HISTFILESIZE))
| project TimeGenerated, DeviceId, DeviceName, AccountName, ProcessId, FileName, ProcessCommandLine, HISTFILESIZE
| summarize arg_max(TimeGenerated, *) by DeviceId, ProcessId, ProcessCommandLine
| order by TimeGenerated desc
pass227.65s0.0076
gpt-5-mini-medium
no answer
no query generatedfail50.00s0.0157
gpt-5-nano-high
0
DeviceProcessEvents
| where (InitiatingProcessFileName contains "bash" or ProcessCommandLine contains "bash" or InitiatingProcessCommandLine contains "bash")
| where (InitiatingProcessCommandLine contains "export HISTFILESIZE=" or ProcessCommandLine contains "export HISTFILESIZE=")
| extend HistFileSizeFromInitiatingExport = extract(@"export\s+HISTFILESIZE\s*=\s*(\d+)", 1, InitiatingProcessCommandLine)
| extend HistFileSizeFromProcessExport = extract(@"export\s+HISTFILESIZE\s*=\s*(\d+)", 1, ProcessCommandLine)
| extend HistFileSize = toint(coalesce(HistFileSizeFromInitiatingExport, HistFileSizeFromProcessExport))
| where isnotnull(HistFileSize)
| project TimeGenerated, DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, ProcessCommandLine, HistFileSize
| order by TimeGenerated desc
pass370.37s0.0050
gpt-5-nano-medium
no answer
no query generatedfail50.00s0.0077
grok-3-beta
0
DeviceProcessEvents
| where ProcessCommandLine has 'bash'
| where ProcessCommandLine matches regex @'export\s+HISTFILESIZE=\d+'
| extend HISTFILESIZE_Value = extract(@'HISTFILESIZE=(\d+)', 1, ProcessCommandLine)
| project DeviceName, AccountName, ProcessCommandLine, HISTFILESIZE_Value, Timestamp
| order by Timestamp desc
pass19.36s0.0224
grok-3-mini-beta
0
DeviceProcessEvents
| where FileName contains "bash"
| where ProcessCommandLine contains "export HISTFILESIZE="
| extend HISTValue = extract("export HISTFILESIZE=([^ ]+)", 1, ProcessCommandLine)
| project TimeGenerated, DeviceName, ProcessCommandLine, HISTValue
| order by TimeGenerated desc
pass110.84s0.0017
o1-high
0
DeviceProcessEvents
| where FileName == "bash"
| where ProcessCommandLine has "export HISTFILESIZE="
| extend HISTFILESIZEValue = extract(@"export\s+HISTFILESIZE=(?<histVal>\S+)", 1, ProcessCommandLine)
| project TimeGenerated, DeviceName, AccountName, ProcessCommandLine, HISTFILESIZEValue
pass127.80s0.2306
o1-low
0
DeviceProcessEvents
| where FileName =~ "bash"
| where ProcessCommandLine contains "export HISTFILESIZE="
| parse kind=regex ProcessCommandLine with ".*export HISTFILESIZE=([^ ]+).*" histFileSize
| project TimeGenerated, DeviceName, AccountName, ProcessCommandLine, histFileSize
pass5117.31s0.8059
o3-high
0
// Locate bash commands that export HISTFILESIZE and capture the assigned value
DeviceProcessEvents
| where FileName in~ ("bash", "sh") or ProcessCommandLine has "/bin/bash"
| where ProcessCommandLine has "export" and ProcessCommandLine has "HISTFILESIZE="
// Pull the value that immediately follows the assignment (stops at the first whitespace or semicolon)
| extend HistFileSizeValue = extract(@"HISTFILESIZE\s*=\s*([^\s;]+)", 1, ProcessCommandLine)
| where isnotempty(HistFileSizeValue)
| project TimeGenerated, DeviceName, AccountName, FileName, ProcessCommandLine, HistFileSizeValue
| sort by TimeGenerated desc
pass138.17s0.0218
o3-mini-high
0
DeviceProcessEvents
| where FileName has "bash" and ProcessCommandLine contains "export HISTFILESIZE"
| extend HistfileSize = extract(@"export\s+HISTFILESIZE[=\s]+(\S+)", 1, ProcessCommandLine)
| project TimeGenerated, DeviceName, AccountName, FileName, ProcessCommandLine, HistfileSize
pass18.73s0.0081
o3-mini-low
0
DeviceProcessEvents
| where FileName contains "bash"
| where ProcessCommandLine contains "export HISTFILESIZE="
| extend HISTFILESIZEValue = extract("export\\s+HISTFILESIZE=([^\\s]+)", 1, ProcessCommandLine)
| project TimeGenerated, ProcessCommandLine, HISTFILESIZEValue
pass216.30s0.0189
o4-mini-high
0
DeviceProcessEvents
| where FileName == "bash"
| where ProcessCommandLine contains "HISTFILESIZE"
| extend HistFileSize = extract(@"HISTFILESIZE\s*=\s*([^;\s]+)", 1, ProcessCommandLine)
| where isnotempty(HistFileSize)
| project TimeGenerated, DeviceName, AccountName, ProcessCommandLine, HistFileSize
pass131.44s0.0097
o4-mini-low
0
DeviceProcessEvents
// Rely on the platform's time picker for the timerange
| where FileName == "bash" or ProcessCommandLine has "bash"
| where ProcessCommandLine has "export HISTFILESIZE"
// Extract the HISTFILESIZE value using regex
| extend HISTFILESIZE_Value = extract(@"HISTFILESIZE\s*=\s*([^; ]+)", 1, ProcessCommandLine)
| project TimeGenerated, DeviceName, AccountName, ProcessId, ProcessCreationTime, ProcessCommandLine, HISTFILESIZE_Value
| order by TimeGenerated desc
pass160.91s0.0098