asa - Linux


asa is a versatile Linux command that provides advanced string manipulation capabilities, including searching, replacing, filtering, and analysis. It is commonly used for processing text files, manipulating data, and performing complex string operations in shell scripts.


asa [options] [pattern] [file(s)]


  • -i: Ignore case during matching.
  • -w: Match whole words only.
  • -h: Display help information.
  • -v: Verbose mode; print additional information about matches.
  • -l: List matching lines only.
  • -n: Print line numbers in the output.
  • -c: Print a count of matches only.
  • -r: Recursively search through subdirectories.
  • -f: Treat each file argument as a single line of text.
  • -e: Interpret pattern as an extended regular expression.


Simple search:

asa "error" log.txt

Replace a string:

asa -i "Disk full" "Disk usage exceeded" log.txt

Filter lines containing a specific word:

asa -w "failed" system.log | grep -v "user error"

Count occurrences of a pattern:

asa -c "connection refused" /var/log/auth.log

Common Issues

  • Ensure the pattern syntax is correct, especially if using extended regular expressions.
  • Verify the target file(s) exist and have appropriate permissions.
  • Be cautious of excessive search patterns that may lead to performance issues.


Combine with other commands:

sudo find / -iname "*.log" | asa -i "error"

Create custom scripts:


# Script to search for and backup log files with errors

asa -i "error" *.log > errors.txt
tar -cvzf errors.tar.gz errors.txt

Related Commands

  • grep: Search for patterns in text files.
  • sed: Perform text substitution and editing.
  • awk: Extract and process data from text files.