This is a General Purpose Tool that reads lines of text from Standard Input.
Lines that match the PCRE regular expression become eligible for output (multiple groups are allowed).
Output is formatted with a "printf" formatting specification (similar to AWK, Perl, C),
with matched group value positional values passed to the printf spec in any order desired.
Make use of your Regular Expression super-powers!
- Allows data transformations with no extra programming.
- Useful as an ad-hoc filter or data tranformation tool
- Command output from a program can be piped into regex_stdin.pl to be filtered or transformed
- Cat a file or use unix command pipe as input ... piped to regex_stdin.pl to be filtered or transformed
- Send logging output through regex_stdin.pl to identify specifix error messages or other conditions that match a given regular expression
- Used as part of a shell script for string transformations in variable assignments
- Use printf_stdin.pl to generate custom commands based groups matched and the formatting specification
- Use printf_stdin.pl as a tool for data profiling by extracting a specific group match that can then be passed to "| sort | uniq -c"
- Use printf_stdin.pl to display the line numbers and full text where match occurred (NUMROWS)
- Use printf_stdin.pl to display how many matches occurred (MATCHCOUNT)
- Use printf_stdin.pl to display how many out of total number of rows that matched (MATCHSUMMARY)
- Very little at all.
- Perl verion 5.xx is all that is required, which is normally on Unix, Linux, AIX by default.
To get the version of perl... try:
perl -v - regex_stdin.pl should work fine on MacOS if perl is installed.
- regex_stdin.pl will work with Windows version that supports ActiveState Perl or Strawberry Perl (5.xx)
- (Tested on versions of Perl ... 5.6 through 5.28)
- (https://www.rexegg.com/regex-quickstart.html)
- (https://cheatography.com/davechild/cheat-sheets/regular-expressions/)
- (https://devhints.io/regexp)
- (https://regexcheatsheet.com/)
regex_stdin.pl takes "regex" as the first parameter)
| Examples | Descr, Cmd, Output |
|---|---|
| match 4 paren groupings, notice the group position numbers are passed to the format string in a different order |
Description: grp1: (line begins with integer) space char grp2: (the word "quick") space char grp3: (1 or more non-space chars) space char grp4: (remaining chars up to end of line) linefeed char Cmd: echo "22 quick brown foxes" | \ ./regex_stdin.pl "^(/d+)\s(quick)\s(\S+)\s(.*)$" "%i %s %s and %s" 1 4 2 3 Output: 22 foxes quick and brown |
| example2 | more docs to come |