Bash script builds correct $cmd but fails to execute complex stream

Question

This short script scrapes some log files daily to create a simple extract. It works from the command line and when I echo the $cmd and copy/paste, it also works. But it will breaks when I try to execute from the script itself.

I know this is a nightmare of patterns that I could probably improve, but am I missing something simple to just execute this correctly?

#!/bin/bash
priorday=$(date --date yesterday +"%Y-%m-%d")
outputfile="/home/CCHCS/da14/$priorday""_PROD_message_processing_times.txt"
cmd="grep 'Processed inbound' /home/rules/care/logs/RootLog* | cut -f5,6,12,16,18 -d\" \" | grep '^"$priorday"' | sed 's/\,/\./' | sed 's/ /\t/g' | sed -r 's/([0-9]+\-[0-9]+\-[0-9]+)\t/\1 /' | sed 's/  / /g' | sort >$outputfile"
printf "command to execute:\n"
echo $cmd
printf "\n"
$cmd

ouput:

./make_log_extract.sh command to execute: grep 'Processed inbound' /home/rules/care/logs/RootLog.log /home/rules/care/logs/RootLog.log.1 /home/rules/care/logs/RootLog.log.10 /home/rules/care/logs/RootLog.log.11 /home/rules/care/logs/RootLog.log.12 /home/rules/care/logs/RootLog.log.2 /home/rules/care/logs/RootLog.log.3 /home/rules/care/logs/RootLog.log.4 /home/rules/care/logs/RootLog.log.5 /home/rules/care/logs/RootLog.log.6 /home/rules/care/logs/RootLog.log.7 /home/rules/care/logs/RootLog.log.8 /home/rules/care/logs/RootLog.log.9 | cut -f5,6,12,16,18 -d" " | grep '^2014-01-30' | sed 's/\,/./' | sed 's/ /\t/g' | sed -r 's/([0-9]+-[0-9]+-[0-9]+)\t/\1 /' | sed 's/ / /g' | sort /home/CCHCS/da14/2014-01-30_PROD_message_processing_times.txt

grep: 5,6,12,16,18: No such file or directory

Basically, try not to do it: stackoverflow.com/questions/794728/… — grebneke
– grebneke, Commented Jan 31, 2014 at 16:05

Community · Accepted Answer · 2017-05-23 12:28:38Z

3

As grebneke comments, do not store the command and then execute it.

What you can do is to execute it but firstly print it: Bash: Print each command before executing?

priorday=$(date --date yesterday +"%Y-%m-%d")
outputfile="/home/CCHCS/da14/$priorday""_PROD_message_processing_times.txt"

set -o xtrace # <-- set printing mode "on"
grep 'Processed inbound' /home/rules/care/logs/RootLog* | cut -f5,6,12,16,18 -d\" \" | grep '^"$priorday"' | sed 's/\,/\./' | sed 's/ /\t/g' | sed -r 's/([0-9]+\-[0-9]+\-[0-9]+)\t/\1 /' | sed 's/  / /g' | sort >$outputfile"
set +o xtrace # <-- revert to normal

edited May 23, 2017 at 12:28

CommunityBot

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answered Jan 31, 2014 at 15:59

fedorqui

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4 Comments

grebneke Over a year ago

+1, what is the difference between set -x and set -o xtrace, if any?

fedorqui Over a year ago

From what I see in tldp.org/LDP/Bash-Beginners-Guide/html/sect_02_03.html, it is exactly the same. Just short & long notation.

chepner Over a year ago

Single-character shell options can also be used when starting bash: bash -x is equivalent to starting bash then executing set -x.

DaveA Over a year ago

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