[CentOS] Off Topic bash question

Thu Jul 23 14:27:37 UTC 2020
Pierre Malard <plm at teledetection.fr>

Hi,

Some remarks:
- just try « expr ${VAR} + 1 » (with blanc between car)
- use simple redirection (« < ») with  a simple reference to file (« done < list.txt »)
- use « ${VAR} » to manage variables
- you can use numeric notation to increment VAR (p.e. « total=$(( ${total} + 1 )) »)

An other way to do that: AWK.

Regards

> Le 23 juil. 2020 à 15:46, Jerry Geis <jerry.geis at gmail.com> a écrit :
> 
> I have a simple script:
> #!/bin/bash
> #
> index=0
> total=0
> names=()
> ip=()
> while read -r LINE
> do
> NODENAME=`   echo $LINE | cut -f 1 -d ','`
> IP=`         echo $LINE | cut -f 2 -d ','`
> names[index]="$NODENAME"
> ip[index]="$IP"
> index=`expr index+1`
> total=`expr total+1`
> done <<< $(cat list.txt)
> 
> simple file:
> more list.txt
> name1,ip1
> name2,ip2
> name3,ip3
> 
> output when running:
> sh -x ./test_bash.sh
> + index=0
> + total=0
> + names=()
> + ip=()
> ++ cat list.txt
> + read -r LINE
> ++ echo name1,ip1 name2,ip2 name3,ip3
> ++ cut -f 1 -d ,
> + NODENAME=name1
> ++ echo name1,ip1 name2,ip2 name3,ip3
> ++ cut -f 2 -d ,
> + IP='ip1 name2'
> + names[index]=name1
> + ip[index]='ip1 name2'
> ++ expr index+1
> + index=index+1
> ++ expr total+1
> + total=total+1
> + read -r LINE
> + echo name1
> name1
> 
> 
> Question is why is it not reading one line at a time ?
> All I get is the first one.
> I'm just trying to build the array of the items in the file and then list
> them at this point.
> 
> Thanks
> 
> Jerry
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Pierre Malard
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IRD - UMR Espace-Dev - UMS CPST
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