AWK hints

README.md

Following are some hints

• There are many flavors for awk, mawkminimal&default, gawkfeature-full & nawknew-implementation
• For a technical comparison between mawk and gawk follow this google discussion
• MAWK was slow, follow this guide. But the recent version 1.3.4 seems to fix that
• AWKPATH is only available in gawk. nawk may have it too. But the default one mawk only uses the -f notation, it doesn't even havet the @inlcude statement, thus one can't nest the files, without creating a wrapper application, in a conf/lib like directory structure.

examples.md

To get the uid and gid from the cli use

# The -F field separator accepts regular expressions
# which allows the following usage
echo $(id | awk -F'[ =(]' '{print $2}'):$(id | awk -F'[ =(]' '{print $5}')
# example output is 1000:1000 or 0:0 for the root

• Regex Matching: Use $1 ~ /[A-Za-z]/ instead of $1 ~= [A-Za-z].
  Follow this SOA for details
• awk to concatenate bash strings: Use echo "input" | awk '{print $1"string"}'
• awk to run system calls based on input: Use awk '{system("mv -R " $1 " " $2)}' file.cfg
• Checking integers in AWK is not simple.
• One can't use env variables/bash-function-positional-args directly in AWK, but can pass them through -v flag