When parsing command output or log files, we often need to identify numeric values that exceed specific thresholds. In the robocopy example, we want to detect files exceeding a size limit (like 10MB) from the output format: *EXTRA File 78223 C:\_Google.Enterprise.Contract.2010-06-01.pdf

While grep and sed can't perform arithmetic comparisons directly, we can combine them with awk for numeric processing:

# Using awk for direct numeric comparison
robocopy_output | awk '$3 > 10485760 {print}'

# Alternative with grep for pattern extraction
grep -Eo '*EXTRA File +[0-9]+' | awk '{if ($3 > 10485760) print $0}'

For more complex log formats, we can use regular expressions with sed and numeric conversion:

# Extract and compare numbers using sed + bash arithmetic
threshold=10485760
while read -r line; do
    size=$(sed -n 's/.*EXTRA File *$[0-9]\+$.*/\1/p' <<< "$line")
    if [[ $size -gt $threshold ]]; then
        echo "$line"
    fi
done < robocopy.log

For large files, consider these optimizations:

# Fastest approach for massive files (single awk process)
awk '/\*EXTRA File/ && $3+0 > 10485760' large_log.txt

Here's a complete script to filter oversized files from robocopy output:

#!/bin/bash
MIN_SIZE_MB=10
BYTES_LIMIT=$((MIN_SIZE_MB * 1024 * 1024))

robocopy source dest /L /NJH /NJS /NP /NS /NC | \
awk -v limit="$BYTES_LIMIT" '
    /\*EXTRA File/ && $3+0 > limit {
        printf "[%dMB] %s\\n", $3/1024/1024, $0
    }'

When parsing log files or command output, we often need to identify numeric values that exceed certain thresholds. The original question deals with extracting file sizes from robocopy output and comparing them against a limit (10MB in this case).

While grep alone can't do numeric comparisons, we can use regular expressions to filter lines containing potential matches:

grep -E '[0-9]{6,}' file.log

This finds numbers with 6+ digits (assuming files over 100KB), but doesn't actually compare values.

Here's a complete sed solution that extracts the size and performs the comparison:

sed -n 's/.*[^0-9]\$[0-9]\\{5,\\}\$[^0-9].*/\\1/p' file.log | \\
while read size; do
  if [ $size -gt 10485760 ]; then
    echo "Large file found: $size"
  fi
done

A more robust solution combines grep with awk for numeric processing:

grep -oP '\\s\\d{5,}\\s' file.log | awk '$1 > 10485760'

For more complex scenarios, Perl offers powerful text processing:

perl -ne 'print if /(\\d+)/ && $1 > 10485760' file.log

Here's how to integrate this with robocopy output:

robocopy source dest /L /NJH /NJS /NP /NDL /NC /NS | \\
grep -oP '\\s\\d{5,}\\s' | \\
awk '$1 > 10485760 {print "File exceeds 10MB: ", $1}'

Remember to consider:

• Files with commas in numbers (e.g., 10,000,000)
• Negative numbers (though not applicable for file sizes)
• Scientific notation (though rare in this context)