Smarter than Grep: What Happens When You Let an LLM Read Your Logs?

Good old software engineering has long relied on Bash scripts to handle small but critical tasks. Whether it’s scheduling cron jobs, managing files, or automating routine system processes, Bash has remained a brutally simple, fast, and dependable tool for every engineer. But with the rise of the AI revolution — I’ve been experimenting with a new kind of automation. One that doesn’t depend on hard-coded logic, but instead on reasoning. LLMs that can not only perform many of the same functions as Bash scripts, but do so while sparing me the technical minutiae of scripting. reasoning This post explores a question I’ve been genuinely curious about: Can large language models (LLMs) complement or even replace traditional Bash scripts for managing real-world infrastructure tasks? I put this to the test using some of my own tools — and honestly, I was surprised by how well an LLM could interpret logs and surface meaningful insights, with zero scripting involved. Can large language models (LLMs) complement or even replace traditional Bash scripts for managing real-world infrastructure tasks? Let’s take a simple use case to demonstrate - Extract last 10 critical error entries from a system log (e.g., /var/log/syslog) and generate a human-readable summary of what went wrong. last 10 critical error entries /var/log/syslog human-readable summary The Traditional Way: Bash Scripts Still Rock A simple bash script that can be used to perform the task at hand: #!/bin/bash grep -iE "error|fail" /var/log/syslog | tail -n 10 #!/bin/bash grep -iE "error|fail" /var/log/syslog | tail -n 10 If we break down the above line, - grep: searches text using patterns - -i: case-insensitive matching (matches "ERROR", "error", etc.) - -E: enables extended regex (lets you use | as "OR") - "error|fail": matches lines that contain either "error" or "fail" - /var/log/syslog: the file being searched - | tail -n 10: pipes the results into tail, which returns the last 10 lines - grep: searches text using patterns - -i: case-insensitive matching (matches "ERROR", "error", etc.) - -E: enables extended regex (lets you use | as "OR") - "error|fail": matches lines that contain either "error" or "fail" - /var/log/syslog: the file being searched - | tail -n 10: pipes the results into tail, which returns the last 10 lines The result of the above command will show the 10 most recent log lines that contain "error" or "fail". (as our expected result from the problem statement) Now lets’ take a look a an example output Apr 21 10:15:01 myhost CRON[31582]: (root) CMD (run-parts /etc/cron.hourly) Apr 21 10:15:02 myhost systemd[1]: Failed to start Network Time Synchronization. Apr 21 10:16:05 myhost kernel: [12345.67] CPU0: Core temperature above threshold, cpu clock throttled Apr 21 10:18:11 myhost systemd[1]: Starting Cleanup of Temporary Directories... Apr 21 10:18:12 myhost systemd[1]: Finished Cleanup of Temporary Directories. Apr 21 10:20:43 myhost sshd[31612]: Failed password for invalid user admin from 192.168.1.5 port 60522 ssh2 Apr 21 10:21:00 myhost sudo[31645]: pam_unix(sudo:auth): authentication failure; logname= uid=1000 euid=0 tty=/dev/pts/0 ruser=user rhost= user=user Apr 21 10:21:05 myhost systemd[1]: Failed to start User Manager for UID 1001. Apr 21 10:22:34 myhost app[31710]: Error loading configuration: file not found Apr 21 10:23:15 myhost docker[31750]: container failed to start due to missing environment variable Apr 21 10:15:01 myhost CRON[31582]: (root) CMD (run-parts /etc/cron.hourly) Apr 21 10:15:02 myhost systemd[1]: Failed to start Network Time Synchronization. Apr 21 10:16:05 myhost kernel: [12345.67] CPU0: Core temperature above threshold, cpu clock throttled Apr 21 10:18:11 myhost systemd[1]: Starting Cleanup of Temporary Directories... Apr 21 10:18:12 myhost systemd[1]: Finished Cleanup of Temporary Directories. Apr 21 10:20:43 myhost sshd[31612]: Failed password for invalid user admin from 192.168.1.5 port 60522 ssh2 Apr 21 10:21:00 myhost sudo[31645]: pam_unix(sudo:auth): authentication failure; logname= uid=1000 euid=0 tty=/dev/pts/0 ruser=user rhost= user=user Apr 21 10:21:05 myhost systemd[1]: Failed to start User Manager for UID 1001. Apr 21 10:22:34 myhost app[31710]: Error loading configuration: file not found Apr 21 10:23:15 myhost docker[31750]: container failed to start due to missing environment variable From the above logs, we can see multiple issues about systemd processes failing to start, CPU overheating warnings, App config and container startup issues. With a bash script, the processs stops at raw data. It is up-to user to understand and intrept the output, perform root cause analysis and fixes. In summary, The output has no context The output has no categorization No explanation of what do to next The output has no context The output has no categorization No explanation of what do to next The AI Alternative: Using LLMs for Log Summarization Here is where LLMs come in! What if we can add another step to this process to make it earlier for a user to understand the meaning of these errors and guide them with troubleshooting steps? In this example, I’ve used a simple summarization API from Cohere. To run it, you’ll need to create an API key from Cohere (or a similar LLM provider) and assign it to cohere_api_key. import cohere cohere_api_key="Enter key here" co = cohere.Client(cohere_api_key) log_text = """ Apr 21 10:15:01 myhost CRON[31582]: (root) CMD (run-parts /etc/cron.hourly) Apr 21 10:15:02 myhost systemd[1]: Failed to start Network Time Synchronization. Apr 21 10:16:05 myhost kernel: [12345.67] CPU0: Core temperature above threshold, cpu clock throttled Apr 21 10:18:11 myhost systemd[1]: Starting Cleanup of Temporary Directories... Apr 21 10:18:12 myhost systemd[1]: Finished Cleanup of Temporary Directories. Apr 21 10:20:43 myhost sshd[31612]: Failed password for invalid user admin from 192.168.1.5 port 60522 ssh2 Apr 21 10:21:00 myhost sudo[31645]: pam_unix(sudo:auth): authentication failure; logname= uid=1000 euid=0 tty=/dev/pts/0 ruser=user rhost= user=user Apr 21 10:21:05 myhost systemd[1]: Failed to start User Manager for UID 1001. Apr 21 10:22:34 myhost app[31710]: Error loading configuration: file not found Apr 21 10:23:15 myhost docker[31750]: container failed to start due to missing environment variable """ prompt = f""" You are an AI system assistant. Here are recent log entries: {log_text} Summarize: 1. What went wrong 2. Any recurring or serious issues 3. Suggested next steps """ response = co.generate( model="command-xlarge", prompt=prompt, max_tokens=200 ) print(response.generations[0].text) import cohere cohere_api_key="Enter key here" co = cohere.Client(cohere_api_key) log_text = """ Apr 21 10:15:01 myhost CRON[31582]: (root) CMD (run-parts /etc/cron.hourly) Apr 21 10:15:02 myhost systemd[1]: Failed to start Network Time Synchronization. Apr 21 10:16:05 myhost kernel: [12345.67] CPU0: Core temperature above threshold, cpu clock throttled Apr 21 10:18:11 myhost systemd[1]: Starting Cleanup of Temporary Directories... Apr 21 10:18:12 myhost systemd[1]: Finished Cleanup of Temporary Directories. Apr 21 10:20:43 myhost sshd[31612]: Failed password for invalid user admin from 192.168.1.5 port 60522 ssh2 Apr 21 10:21:00 myhost sudo[31645]: pam_unix(sudo:auth): authentication failure; logname= uid=1000 euid=0 tty=/dev/pts/0 ruser=user rhost= user=user Apr 21 10:21:05 myhost systemd[1]: Failed to start User Manager for UID 1001. Apr 21 10:22:34 myhost app[31710]: Error loading configuration: file not found Apr 21 10:23:15 myhost docker[31750]: container failed to start due to missing environment variable """ prompt = f""" You are an AI system assistant. Here are recent log entries: {log_text} Summarize: 1. What went wrong 2. Any recurring or serious issues 3. Suggested next steps """ response = co.generate( model="command-xlarge", prompt=prompt, max_tokens=200 ) print(response.generations[0].text) Let’s see the output from the above program: The recent log entries indicate several issues: 1. There are errors and failures mentioned across different services, indicating some system instability. These include: - Failed attempts to authenticate invalid users for SSH and sudo. - cron and systemd errors starting the Network Time Synchronization and Cleanup of Temporary Directories. - Failure to start the User Manager for UID 1001. - An application error loading the configuration file. - A Docker container failure due to a missing environment variable. 2. Based on the log entries, no single issue is particularly recurring, but several different errors are frequent enough to be cause for concern. 3. It is suggested to investigate and address the specific causes of the aforementioned issues to ensure the system functions optimally and securely. This may include reviewing authentication settings, checking system services configurations, verifying file locations for the configuration file, and inspecting the Docker container settings. Also, it is important to consider if any messages are explicitly highlighted across the logs, The recent log entries indicate several issues: 1. There are errors and failures mentioned across different services, indicating some system instability. These include: - Failed attempts to authenticate invalid users for SSH and sudo. - cron and systemd errors starting the Network Time Synchronization and Cleanup of Temporary Directories. - Failure to start the User Manager for UID 1001. - An application error loading the configuration file. - A Docker container failure due to a missing environment variable. 2. Based on the log entries, no single issue is particularly recurring, but several different errors are frequent enough to be cause for concern. 3. It is suggested to investigate and address the specific causes of the aforementioned issues to ensure the system functions optimally and securely. This may include reviewing authentication settings, checking system services configurations, verifying file locations for the configuration file, and inspecting the Docker container settings. Also, it is important to consider if any messages are explicitly highlighted across the logs, Now, let’s level up the prompt a bit to get a structured output, along with the chat API endpoint. response = co.chat( model="command-r", message=f""" You are a system assistant. Given the logs below, extract all relevant issues and organize them into a table with these three columns: 1. Issue 2. Severity (Low / Medium / High / Critical) 3. Troubleshooting Recommendation""") response = co.chat( model="command-r", message=f""" You are a system assistant. Given the logs below, extract all relevant issues and organize them into a table with these three columns: 1. Issue 2. Severity (Low / Medium / High / Critical) 3. Troubleshooting Recommendation""") Here’s the result generated by the LLM: Issue Severity Troubleshooting Recommendation Network Time Synchronization failed to start Medium Check the system logs for any timing out or failed network requests and ensure the time zone settings are correct. CPU temperature above threshold, cpu clock throttled High Monitor the CPU temperature and consider adding CPU cooling solutions. The performance of the CPU might be affected. Failed password attempt from invalid user Low No immediate action required, but monitor for suspicious activity. Recommend ensuring strong passwords and enabling two-factor authentication. Authentication failure for user Low Ensure the user's permissions and authentication methods are set up correctly. Check for typos or misconfigurations. User Manager for UID 1001 failed to start Medium Investigate the specific error message and check if the user account is active and exists. Error loading configuration: file not found High Locate the missing configuration file and ensure the file path is correct. The application may not function properly until this is resolved. Docker container failure due to missing environment variable Critical Check the container configuration and ensure the required environment variables are set. The application or service dependent on this container may not be functioning. Issue Severity Troubleshooting Recommendation Network Time Synchronization failed to start Medium Check the system logs for any timing out or failed network requests and ensure the time zone settings are correct. CPU temperature above threshold, cpu clock throttled High Monitor the CPU temperature and consider adding CPU cooling solutions. The performance of the CPU might be affected. Failed password attempt from invalid user Low No immediate action required, but monitor for suspicious activity. Recommend ensuring strong passwords and enabling two-factor authentication. Authentication failure for user Low Ensure the user's permissions and authentication methods are set up correctly. Check for typos or misconfigurations. User Manager for UID 1001 failed to start Medium Investigate the specific error message and check if the user account is active and exists. Error loading configuration: file not found High Locate the missing configuration file and ensure the file path is correct. The application may not function properly until this is resolved. Docker container failure due to missing environment variable Critical Check the container configuration and ensure the required environment variables are set. The application or service dependent on this container may not be functioning. Issue Severity Troubleshooting Recommendation Issue Issue Severity Severity Troubleshooting Recommendation Troubleshooting Recommendation Network Time Synchronization failed to start Medium Check the system logs for any timing out or failed network requests and ensure the time zone settings are correct. Network Time Synchronization failed to start Network Time Synchronization failed to start Medium Medium Check the system logs for any timing out or failed network requests and ensure the time zone settings are correct. Check the system logs for any timing out or failed network requests and ensure the time zone settings are correct. CPU temperature above threshold, cpu clock throttled High Monitor the CPU temperature and consider adding CPU cooling solutions. The performance of the CPU might be affected. CPU temperature above threshold, cpu clock throttled CPU temperature above threshold, cpu clock throttled High High Monitor the CPU temperature and consider adding CPU cooling solutions. The performance of the CPU might be affected. Monitor the CPU temperature and consider adding CPU cooling solutions. The performance of the CPU might be affected. Failed password attempt from invalid user Low No immediate action required, but monitor for suspicious activity. Recommend ensuring strong passwords and enabling two-factor authentication. Failed password attempt from invalid user Failed password attempt from invalid user Low Low No immediate action required, but monitor for suspicious activity. Recommend ensuring strong passwords and enabling two-factor authentication. No immediate action required, but monitor for suspicious activity. Recommend ensuring strong passwords and enabling two-factor authentication. Authentication failure for user Low Ensure the user's permissions and authentication methods are set up correctly. Check for typos or misconfigurations. Authentication failure for user Authentication failure for user Low Low Ensure the user's permissions and authentication methods are set up correctly. Check for typos or misconfigurations. Ensure the user's permissions and authentication methods are set up correctly. Check for typos or misconfigurations. User Manager for UID 1001 failed to start Medium Investigate the specific error message and check if the user account is active and exists. User Manager for UID 1001 failed to start User Manager for UID 1001 failed to start Medium Medium Investigate the specific error message and check if the user account is active and exists. Investigate the specific error message and check if the user account is active and exists. Error loading configuration: file not found High Locate the missing configuration file and ensure the file path is correct. The application may not function properly until this is resolved. Error loading configuration: file not found Error loading configuration: file not found High High Locate the missing configuration file and ensure the file path is correct. The application may not function properly until this is resolved. Locate the missing configuration file and ensure the file path is correct. The application may not function properly until this is resolved. Docker container failure due to missing environment variable Critical Check the container configuration and ensure the required environment variables are set. The application or service dependent on this container may not be functioning. Docker container failure due to missing environment variable Docker container failure due to missing environment variable Critical Critical Check the container configuration and ensure the required environment variables are set. The application or service dependent on this container may not be functioning. Check the container configuration and ensure the required environment variables are set. The application or service dependent on this container may not be functioning. Beyond LLMs: Enter the AI Agent This is solid, but it could use just a bit more energy to tee up the comparison table. While Bash has served as a reliable workhorse for system automation, and LLMs offer a huge leap in interpreting infrastructure data like logs, they both operate within well-defined bounds. Bash is deterministic and fast, while LLMs are contextual and flexible — but still rely on human-triggered prompts. This is where AI agents come in. AI agents Agents go one step further — they’re not just responding to prompts, they’re designed to act on goals, use tools, make decisions, and even loop through retries or escalate issues autonomously. Imagine a system that doesn't just summarize errors but reads logs, correlates events, checks service health, and opens a Jira ticket — all without you lifting a finger. act on goals Bash vs LLMs vs AI Agents Here's a quick comparison to highlight how these approaches differ: Feature / Capability Bash LLM AI Agent Task execution Single-purpose scripts One-off summarization or reasoning Multi-step, goal-driven workflows Error detection Grep/filter with keywords Understands and summarizes errors in context Detects, interprets, and responds with follow-up actions Output format Raw text or structured output Human-readable summary / structured response Can return summaries, alerts, logs, or take real-time actions Context awareness ❌ No ✅ Some (within prompt length) ✅✅ Maintains memory, can iterate on inputs Decision making ❌ Hardcoded logic ⚠️ Limited (only within prompt instructions) ✅ Yes — can reason and choose tools based on needs Autonomy ❌ Manual invocation ❌ Needs human prompt ✅ Can operate with high-level goals, retry, escalate Tool use CLI utilities API or local inference only Integrates tools like system checks, logs, alerts, APIs Adaptability ❌ Static ⚠️ Prompt-dependent ✅ Learns & adapts within session or flow Code complexity ✅ Simple (but verbose over time) ✅ Simple (few lines with prompt) ⚠️ More complex (needs orchestration logic) Best for Simple, repeatable tasks Interpretation, summarization, classification Complex infra automation, real-time monitoring, remediation Feature / Capability Bash LLM AI Agent Task execution Single-purpose scripts One-off summarization or reasoning Multi-step, goal-driven workflows Error detection Grep/filter with keywords Understands and summarizes errors in context Detects, interprets, and responds with follow-up actions Output format Raw text or structured output Human-readable summary / structured response Can return summaries, alerts, logs, or take real-time actions Context awareness ❌ No ✅ Some (within prompt length) ✅✅ Maintains memory, can iterate on inputs Decision making ❌ Hardcoded logic ⚠️ Limited (only within prompt instructions) ✅ Yes — can reason and choose tools based on needs Autonomy ❌ Manual invocation ❌ Needs human prompt ✅ Can operate with high-level goals, retry, escalate Tool use CLI utilities API or local inference only Integrates tools like system checks, logs, alerts, APIs Adaptability ❌ Static ⚠️ Prompt-dependent ✅ Learns & adapts within session or flow Code complexity ✅ Simple (but verbose over time) ✅ Simple (few lines with prompt) ⚠️ More complex (needs orchestration logic) Best for Simple, repeatable tasks Interpretation, summarization, classification Complex infra automation, real-time monitoring, remediation Feature / Capability Bash LLM AI Agent Feature / Capability Feature / Capability Bash Bash Bash LLM LLM LLM AI Agent AI Agent AI Agent Task execution Single-purpose scripts One-off summarization or reasoning Multi-step, goal-driven workflows Task execution Task execution Task execution Single-purpose scripts Single-purpose scripts One-off summarization or reasoning One-off summarization or reasoning Multi-step, goal-driven workflows Multi-step, goal-driven workflows Error detection Grep/filter with keywords Understands and summarizes errors in context Detects, interprets, and responds with follow-up actions Error detection Error detection Error detection Grep/filter with keywords Grep/filter with keywords Understands and summarizes errors in context Understands and summarizes errors in context Detects, interprets, and responds with follow-up actions Detects, interprets, and responds with follow-up actions Output format Raw text or structured output Human-readable summary / structured response Can return summaries, alerts, logs, or take real-time actions Output format Output format Output format Raw text or structured output Raw text or structured output Human-readable summary / structured response Human-readable summary / structured response Can return summaries, alerts, logs, or take real-time actions Can return summaries, alerts, logs, or take real-time actions Context awareness ❌ No ✅ Some (within prompt length) ✅✅ Maintains memory, can iterate on inputs Context awareness Context awareness Context awareness ❌ No ❌ No ✅ Some (within prompt length) ✅ Some (within prompt length) ✅✅ Maintains memory, can iterate on inputs ✅✅ Maintains memory, can iterate on inputs Decision making ❌ Hardcoded logic ⚠️ Limited (only within prompt instructions) ✅ Yes — can reason and choose tools based on needs Decision making Decision making Decision making ❌ Hardcoded logic ❌ Hardcoded logic ⚠️ Limited (only within prompt instructions) ⚠️ Limited (only within prompt instructions) ✅ Yes — can reason and choose tools based on needs ✅ Yes — can reason and choose tools based on needs Autonomy ❌ Manual invocation ❌ Needs human prompt ✅ Can operate with high-level goals, retry, escalate Autonomy Autonomy Autonomy ❌ Manual invocation ❌ Manual invocation ❌ Needs human prompt ❌ Needs human prompt ✅ Can operate with high-level goals, retry, escalate ✅ Can operate with high-level goals, retry, escalate Tool use CLI utilities API or local inference only Integrates tools like system checks, logs, alerts, APIs Tool use Tool use Tool use CLI utilities CLI utilities API or local inference only API or local inference only Integrates tools like system checks, logs, alerts, APIs Integrates tools like system checks, logs, alerts, APIs Adaptability ❌ Static ⚠️ Prompt-dependent ✅ Learns & adapts within session or flow Adaptability Adaptability Adaptability ❌ Static ❌ Static ⚠️ Prompt-dependent ⚠️ Prompt-dependent ✅ Learns & adapts within session or flow ✅ Learns & adapts within session or flow Code complexity ✅ Simple (but verbose over time) ✅ Simple (few lines with prompt) ⚠️ More complex (needs orchestration logic) Code complexity Code complexity Code complexity ✅ Simple (but verbose over time) ✅ Simple (but verbose over time) ✅ Simple (few lines with prompt) ✅ Simple (few lines with prompt) ⚠️ More complex (needs orchestration logic) ⚠️ More complex (needs orchestration logic) Best for Simple, repeatable tasks Interpretation, summarization, classification Complex infra automation, real-time monitoring, remediation Best for Best for Best for Simple, repeatable tasks Simple, repeatable tasks Interpretation, summarization, classification Interpretation, summarization, classification Complex infra automation, real-time monitoring, remediation Complex infra automation, real-time monitoring, remediation Picking the Right Tool for the Job We’re at interesting crossroads when it comes to automation. Bash is still the go-to for quick, repeatable tasks — and probably always will be. But with LLMs and agents stepping in, there’s a new way to approach problems that demand more context, flexibility, or even decision-making. This isn’t about replacing Bash, but about using the right tool for the job — whether it’s a script, a prompt, or a full-blown autonomous agent. As these technologies mature, I’ve found myself thinking less like a scripter and more like a system architect — connecting tools, shaping workflows, and designing for adaptability.