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BASH replace a line in file

Posted 04-05-2020 at 05:20 PM by karanis

Tags bash

karanis

LQ Newbie

Posted in Uncategorized

Views 324 Comments 0 karanis is offline

BASH extract fields from string

Posted 04-05-2020 at 05:19 PM by karanis

Tags awk, bash

https://en.wikibooks.org/wiki/Cut

link above have nice examples

Examples of use of similar tools in cut's domain:

echo a b|awk '{print $2}'
Displays "b", separating fields by any number of tabs or spaces. Thus, for awk, "b" is the 2nd field, while for cut -d" ", "b" is the 3rd field.
echo a b|awk '{print $2 $1}'
Displays "ba", preserving the order of the fields as specified....

karanis

LQ Newbie

Posted in Uncategorized

Views 379 Comments 0 karanis is offline

BASH read file

Posted 04-05-2020 at 05:17 PM by karanis

Tags bash

https://www.cyberciti.biz/faq/unix-h...ine-from-file/

https://www.computerhope.com/unix/bash/read.htm

https://www.shellhacks.com/bash-read...ead-line-loop/

----------

while read USER; do echo "Hello $USER!"; done < users.txt

----------

#!/bin/ksh
file="/home/vivek/data.txt"
while IFS= read line
do
# display $line...

karanis

LQ Newbie

Posted in Uncategorized

Views 312 Comments 0 karanis is offline

BASH datetime for scripts

Posted 04-05-2020 at 05:16 PM by karanis

Tags bash, time

#!/bin/bash
dt=`date '+%d/%m/%Y %H:%M:%S'`
echo "$dt"

karanis

LQ Newbie

Posted in Uncategorized

Views 297 Comments 0 karanis is offline

BASH get ip from ifconfig ( and grep hostname from /etc/hosts by IP)

Posted 04-05-2020 at 05:13 PM by karanis
Updated 04-05-2020 at 05:15 PM by karanis

Tags bash, net

#!/bin/bash

IP=`/usr/sbin/ip addr show dev eth0| grep -v inet6| awk ' !/127.0.0.1/ && /inet/ { gsub(/\/.*/, "", $2); print $2 }'`
grep $IP /etc/hosts | sed -r s/$IP\\s\\t//

karanis

LQ Newbie

Posted in Uncategorized

Views 798 Comments 0 karanis is offline

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