CODEWITHSUNDEEP
linuxbashloopsunixposix
Learner33
Learner33

Reputation: 131

For loop select specific part of string variable

simple question: I have a variable called x:

echo $x
3122;192.31.231.2 3379;183.3.202.111 3085;218.25.208.92

What I would like is to iterate over the IP's only, not the initial number.

192.31.231.2
183.3.202.111
218.25.208.92

Current code:

for ip in $x; 
do
    echo `geoiplookup "$ip[$2]"`
done

Upvotes: 2

Views: 141

Answers (3)

Jorenar
Jorenar

Reputation: 2884

If we can assume, that between each number and IP address is a semicolon, then we just need to cut until delimiter (i.e. ; in this case) and select second part.

We can do it in such manner: echo $var | cut -d';' -f2

Now to put this back into your code:

for ip in $x; do
    geoiplookup "$(echo $ip | cut -d';' -f2)"
    # wrapping it in `echo` would just print what would be printed either way
done

Upvotes: 3

Timur Shtatland
Timur Shtatland

Reputation: 12377

Use this Perl one-liner, connected to a while loop via a pipe:

perl -lne 'print for /\b\d+;([\d.]+)\b/g' <<<$x | \
    while read -r ip ; do
        echo "my_command ${ip}"
    done

The Perl one-liner uses these command line flags:
-e : Tells Perl to look for code in-line, instead of in a file.
-n : Loop over the input one line at a time, assigning it to $_ by default.
-l : Strip the input line separator ("\n" on *NIX by default) before executing the code in-line, and append it when printing.

/\b\d+;([\d.]+)\b/g - Captures and returns IP addresses. Returns multiple matches (regex /g modifier). Matches \b - a word boundary, followed by \d+; - a stretch of digits ending with a semicolon, followed by [\d.]+ - a stretch of digits or periods, followed by \b - another word boundary.

Upvotes: 1

markp-fuso
markp-fuso

Reputation: 34946

One idea using parameter expansion:

x="3122;192.31.231.2 3379;183.3.202.111 3085;218.25.208.92"

for stuff in ${x}                 # process each '<number>;ip' pair separately
do
    ip="${stuff##*;}"             # strip off leading '<number>;'
    echo "${ip}"
    # geoiplookup "${ip}"
done

NOTE: I'm not familiar with the geoiplookup command so not sure why OP is wrapping the geoiplookup call inside an echo call versus just calling geoiplookup directly ... ??

This generates:

192.31.231.2
183.3.202.111
218.25.208.92

From here the OP can reference ${ip} as needed for the geoiplookup call.

Upvotes: 3

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