LinuxQuestions.org - Bash

- Programming (https://www.linuxquestions.org/questions/programming-9/)

- - Bash_rematch (https://www.linuxquestions.org/questions/programming-9/bash_rematch-945917/)

THe below is a java executalbe - If i execute it from the commnad line, without todays session
it strikes a error.

Code:

casper ~ $ /data/execCommand ntf2201.1 /SPINMASTER/RELEASEALLEQUITIES

ERROR: Must specify the active session: 000005947S

casper ~ $ /data/execCommand ntf2201.1 /SPINMASTER/RELEASEALLEQUITIES 000005947S

Done: RELEASEALLEQUITIES

SO i made this script - which works fine:

Code:

#!/bin/bash

for i in $(grep -i masterexecutor /casper/*commands| perl -nle 'print /(server\d+\.?\d+)/' |sort -u)

        do

        output=$(/data/execCmd $i /SPINMASTER/RELEASEALLEQUITIES | cut -d" " -f7)

        if [[ -n $output ]] ; then  # -n tests to see id the argument is not empty

                echo "/data/execCommand $i /SPINMASTER/RELEASEALLEQUITIES $output"

                /data/execCommand $i /SPINMASTER/RELEASEALLEQUITIES $output

        fi



done

which works fine - However using cut -d is boring.

I was looking into using the BASH_REMATCH - but it does not like the perl like regex \d{9}\w
and when I use the postix, it does not seem to like that either.
Anybody know of a good reference for the BASH_REMATCH?
Can I parse/capture strings with BASH_REMATCH?

Code:

#!/bin/bash

for i in $(grep -i masterexecutpor /var/ftp/*commands| perl -nle 'print /(server\d+\.?\d+)/' |sort -u)

        do

        output=$(/data/execCmd $i /SPINMASTER/RELEASEALLEQUITIES)

        if [[ -n $output ]] ; then  # -n tests to see id the argument is not empty

                if [[ $output =~ ([[:digit:]]*[[:alpha:]]) ]]; then

                /data/execCmd $i /SPINMASTER/RELEASEALLEQUITIES "${BASH_REMATCH[1]}"

                fi

        fi

done

Why not use

Code:

output="${output//[$'\t\n\v\f\r ']/}"

output="${output##*:}"

LANG=C LC_ALL=C

if [ ${#output} -ge 2 -a "$output" = "${output//[^0-9]/}${output//[^A-Za-z]/}" ]; then

instead?

The first line removes all whitespace from output.

The second line removes everything up to and including the final colon from output. This should leave just the identifier in output.

The test checks if output is at least two characters long, and contains digits 0-9 followed by letters A-Z or a-z (either may be omitted). In an UTF-8 locale, [A-Za-z] glob pattern may contain non-ASCII letters (although I think Bash has some bugs here currently). Explicitly setting the locale to POSIX will make sure that does not happen. In fact, you might wish to set the locale at the start of your script, and be done with it.

It sure is ugly, though.

After a second look, I think I'd personally use

Code:

LC_ALL=C LANG=C

output=$(/data/execCmd "$i" /SPINMASTER/RELEASEALLEQUITIES | sed -ne 's|^ERROR.*session: *\([0-9]\+[A-Za-z]*\) *\r*$|\1|p)

if [ -n "$output" ]; then

    echo "/data/execCommand "$i" /SPINMASTER/RELEASEALLEQUITIES $output"

    /data/execCommand "$i" /SPINMASTER/RELEASEALLEQUITIES $output

fi

instead. The sed command replaces the cut, while also making sure the line it uses is correctly formatted, and the identifier itself is acceptable. If not, it outputs nothing.
Note that if there were more than one "ERROR...session:" in the first output, they would all be listed as separate parameters to the command.

OK, I've been up for about 20 hours, so maybe I'm missing something, but AFAICT, you just want the final word from the output, right? If so, why not assign it to array and yank out the final word.

Code:

output=($(/data/execCmd $i /SPINMASTER/RELEASEALLEQUITIES))

output=${output[${#output}-1]}

Or just use awk:

Code:

output=$(/data/execCmd $i /SPINMASTER/RELEASEALLEQUITIES | awk '{print $NF}')

When using exotic items, ie not just straight numbers and letters, i find it is best to store the regex in a variable, so something like the following should work:

Code:

#!/bin/bash



regex=' [[:digit:]]{9}[[:alpha:]]$'



for i in $(grep -i masterexecutpor /var/ftp/*commands| perl -nle 'print /(server\d+\.?\d+)/' |sort -u)

do

    [[ $(/data/execCmd $i /SPINMASTER/RELEASEALLEQUITIES) =~ $regex ]] && /data/execCmd $i /SPINMASTER/RELEASEALLEQUITIES "${BASH_REMATCH[0]}"

done

Untested but you get the idea :)