Logging framework in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this logging command?

Consider this bash script snippet that uses a simple logging function:

log() {
  level=$1
  message=$2
  echo "[$(date +'%Y-%m-%d %H:%M:%S')] $level: $message"
}

log "INFO" "Deployment started"

What will be the output format of the last command?

Bash Scripting

log() {
  level=$1
  message=$2
  echo "[$(date +'%Y-%m-%d %H:%M:%S')] $level: $message"
}

log "INFO" "Deployment started"

A [YYYY-MM-DD HH:MM:SS] INFO: Deployment started

B [INFO] YYYY-MM-DD HH:MM:SS Deployment started

C INFO [YYYY-MM-DD HH:MM:SS]: Deployment started

D Deployment started INFO [YYYY-MM-DD HH:MM:SS]

💡 Hint

Look at how the echo command formats the output string with date and level.

The function prints the date and time in brackets, followed by the log level, a colon, and the message. The date format is YYYY-MM-DD HH:MM:SS.

❓ Configuration

intermediate

Which syslog configuration line sets the log level to 'warning' for a service?

In the syslog configuration file, you want to log only warnings and errors from the 'auth' facility. Which line correctly configures this?

A auth.error /var/log/auth.log

B auth.debug /var/log/auth.log

C auth.warning /var/log/auth.log

D auth.info /var/log/auth.log

💡 Hint

The log level 'warning' includes warnings and errors but excludes info and debug.

The 'auth.warning' selector logs messages with level warning and higher (error, critical, etc.) from the auth facility.

❓ Troubleshoot

advanced

Why does this bash logging function fail to log multi-word messages correctly?

Given this function:

log() {
  echo "[$(date)] $1: $2"
}

log INFO Deployment started successfully

Why does the output only show 'Deployment' instead of the full message?

Bash Scripting

log() {
  echo "[$(date)] $1: $2"
}

log INFO Deployment started successfully

A Because $2 only captures the second word; the rest are ignored without quotes.

B Because date command is missing format specifier.

C Because echo does not support multiple arguments.

D Because the function is missing a return statement.

💡 Hint

Think about how bash handles positional parameters and multiple words.

In bash, $2 refers only to the second argument. The words after the second are separate arguments and not included in $2. To capture the full message, quotes or "$@" are needed.

🔀 Workflow

advanced

What is the correct order to set up a centralized logging system using rsyslog?

Arrange these steps in the correct order to configure a centralized logging server with rsyslog:
1. Configure clients to send logs to the server
2. Install rsyslog on server and clients
3. Configure server to receive remote logs
4. Restart rsyslog service on all machines

A 2,1,3,4

B 1,2,3,4

C 1,3,2,4

D 2,3,1,4

💡 Hint

You must install software before configuring it, and server config before client config.

First install rsyslog everywhere, then configure the server to accept logs, then configure clients to send logs, finally restart services to apply changes.

✅ Best Practice

expert

Which logging practice helps avoid losing logs during high load in a bash script?

You have a bash script that logs messages to a file. Sometimes under heavy load, logs are lost or incomplete. Which practice best prevents this?

A Write logs to a variable and echo all at the end of the script

B Use a logging function that appends logs with '>>' and flushes output immediately

C Use 'echo' without redirection and rely on stdout capture

D Write logs to /dev/null to avoid disk I/O delays

💡 Hint

Think about how to ensure logs are written safely and immediately to disk.

Appending with '>>' ensures logs are added without overwriting. Flushing output immediately reduces risk of losing logs if script crashes or is interrupted.