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Bash Shell Scripting Tips

For Lab 5 Investigation 1 Part 2​

Using awk to Manipulate Text​

  • Very useful command for report generation, text file repair, or text and floating-point decimal manipulation. The command mimics a C program, with braces { } that surround the action to perform based on records from a database file matching either test conditions, regular expressions, etc. Fields appear as numbers with $.
  • Examples:
awk '{print}' data-file.txt
awk -F";" '{print $5,$3}' data-file.txt
awk -F"," '$4 >= 10000 {print $1, $2}' salary.txt

Crontab (Chronograph Tables)​

  • Used to automatically run (as opposed to manually run) scripts, programs, or commands. There are many tables (files), but the main one is: /etc/cron. The crontab command can be used to list, create, modify or remove scheduled jobs in the file.
  • Examples:
crontab -e -u user # create/modify
crontab -r -u user-name # remove specific user's crontab
crontab -l -u username #List current schedules