CODEWITHSUNDEEP
listshellloopscommand-line-arguments
AlexdD1979
AlexdD1979

Reputation: 13

Loop over an shell argument which contains a list of values and write these values to a file

I have a shell script in Linux, which needs as input one argument, which can contains a list of ip adresses. These list needs to be written line by line to a file.

./myTestScript.sh 192.168.100.2,192.168.100.3

In the script, the output to be generated is

192.168.100.2 OK
192.168.100.3 OK

and written to a file called exceptions.map.

MY idea for a single IP works, but how to implement a loop ovre a list from arguments.

#!/bin/sh
IPADRESSES=$1
echo $IPADRESSES
sudo rm /appli/myApp/apps/mainApp/maintenance/exceptions.map
echo $IPADRESSES OK > "/appli/myApp/apps/mainApp/maintenance/exceptions.map"

Upvotes: 1

Views: 50

Answers (3)

xhienne
xhienne

Reputation: 6134

One command, no loop needed:

$ printf '%s OK\n' ${1//,/ } > "/appli/myApp/apps/mainApp/maintenance/exceptions.map"

${1//,/ } splits your command argument by replacing all commas with spaces. printf prints each IP according to your format.

${1//,/ } can also be used in a loop:

for ip in ${1//,/ }; do something with "$ip"; done

Upvotes: 1

cxw
cxw

Reputation: 17041

Here's a pure-bash way:

#!/bin/bash

IFS=, read -ra addresses <<<"$1"
for addr in "${addresses[@]}"; do
    echo "$addr OK"
done > exceptions.map

The IFS=... line reads the comma-separated contents of the first argument $1 into array addresses. They are comma-separated because of IFS=,. The for loop then prints each address in turn, plus the OK.

Upvotes: 0

William Pursell
William Pursell

Reputation: 212208

#!/bin/sh

echo "$1" | tr , \\n | sed 's/$/ OK/' > exceptions.map

Or, if you really want to write a loop:

IFS=,
for i in $1; do
        echo "$i OK"
done

Note that the $1 here must remain unquoted, since we are explicitly relying on word-splitting. But usually, I would change the API a bit and have the caller pass each IP as a separate arugment and do for x; do echo "$x OK"; done.

Upvotes: 1

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