I have this line of code which I would like to hide its output.
Vrs=$(cat $(echo $line | awk -F"-" '{print "/var/AS-"$2"-"toupper($3)"-"$4}') | grep "YES" | cut -d":" -f5)
I have tried to include &> /dev/null at the end of the line but it doesn't work.
Does anyone know how to do this?
I am not exactly sure what you are trying to achieve, but your cat call looks redundant to me.
Vrs=$(echo "$line" | awk -F"-" '{print "/var/AS-"$2"-"toupper($3)"-"$4}' | grep "YES" | cut -d":" -f5)
You could rephrase the statement to
Vrs=$(echo "$line" | awk -F"-" '{print "/var/AS-"$2"-"toupper($3)"-"$4}' | grep "YES" | cut -d":" -f5)
This does the same thing. In the command is successful, you would get the result stored in Vrs. No output would be shown in the stdout. However, if you expect errors, you could do :
Vrs=$(echo "$line" | awk -F"-" '{print "/var/AS-"$2"-"toupper($3)"-"$4}' | grep "YES" | cut -d":" -f5 2>/dev/null)
This will suppress the errors and give you an empty $Vrs
Notes:
I have double quoted $line to prevent globbing and word splitting.
Related
end=echo $FSDB_FILE_NAME | rev | cut -d'_' -f 2 |rev
begin=echo $FSDB_FILE_NAME | rev | cut -d'_' -f 3 |rev
echo $end
echo $begin
echo abc_11204.00_15713.00_.csv | rev | cut -d'_' -f 2 |rev ---- This works
But echo $end is not printing anything
I even tried:
set end=echo abc_11204.00_15713.00_.csv | rev | cut -d'_' -f 2 |rev
echo $end
This prints empty
Please help me with this
Sample input : abc_123.00_345.00_xyz.csv
Output : end=345.00
begin=123.00
Could you please try following. Easy approach with awk.
start=$(echo "$input_variable" | awk -F'_' '{print $2}')
end=$(echo "$input_variable" | awk -F'_' '{print $3}')
When I print variable's values it will be as follows:
echo "$start"
123.00
echo "$end"
345.00
I have a variable with value like:
#capability_ids type="list">[LOADBALANCER]</capability_ids>#
And need to extract from this string type of equipment ( LOADBALANCER ).
I've tried to use cut, but don't know how write cut command with different delimiters.
DeviceType=$( echo $DeviceTypeDirty | cut -d'[' -f1)
Can enywone help me with right solution on bash?
use awk with regular expression: awk -F '[\\[\\]]' '{print $2}'
$ echo '#capability_ids type="list">[L3SWITCH]/capability_ids>#'|awk -F '[\\[\\]]' '{print $2}'
$ L3SWITCH
$ DeviceType=$( echo "$DeviceTypeDirty" | awk -F '[\\[\\]]' '{print $2}')
I tried and got to extract "LOADBALANCER"
Administrators-MacBook-Pro:~$ echo "\"list\">[LOADBALANCER]
</capability_ids>#"|awk -F '[][]' '{print $2}'
LOADBALANCER
Administrators-MacBook-Pro:~$
Hope that helps!
Using cut:
DeviceTypeDirty="#capability_ids type="list">[LOADBALANCER]</capability_ids>#"
DeviceType="$(echo "$DeviceTypeDirty" | cut -d'[' -f2 | cut -d']' -f1)"
Output:
echo "$DeviceType"
LOADBALANCER
I have the following piece of code and would like to display HOST and RESULT side by side with a : separating them.
HOST=`grep pers results.txt | cut -d':' -f2 | awk '{print $1}'`
RESULT=`grep cleanup results.txt | cut -d':' -f2 | awk '{print $1}' | sed -e 's/K/000/' -'s/M/000000/'`
echo ${HOST}${RESULT}
Please can anyone assist with the final command to display these, I am just getting all of hosts and then all of results.
You probably want this:
HOST=( `grep pers results.txt | cut -d':' -f2 | awk '{ print $1 }'` ) #keep the output of the command in an array
RESULT=( `grep cleanup results.txt | cut -d':' -f2 | awk '{ print $1 }' | sed -e 's/K/000/' -'s/M/000000/'` )
for i in "${!HOST[#]}"; do
echo "${HOST[$i]}:${RESULT[$i]}"
done
A version that works without arrays, using an extra file handle to read from 2 sources at at time.
while read host; read result <&3; do
echo "$host:$result"
done < <( grep peers results.txt | cut -d: -f2 | awk '{print $1}' ) \
3< <( grep cleanup results.txt | cut -d':' -f2 | awk '{print $1}' | sed -e 's/K/000/' -'s/M/000000/')
It's still not quite POSIX, as it requires process substitution. You could instead use explicit fifes. (Also, an attempt to shorten the pipelines that produce the hosts and results. It's probably possible to combine this into a single awk command, since you can either do the substitution in awk, or pipe to sed from within awk. But this is all off-topic, so I leave it as an exercise to the reader.)
mkfifo hostsrc
mkfifo resultsrc
awk -F: '/peers/ {split($2, a, ' '); print a[1]}' results.txt > hostsrc &
awk -F: '/cleanup/ {split($2, a, ' '); print a[1]}' results.txt | sed -e 's/K/000' -e 's/M/000000/' > resultsrc &
while read host; read result <&3; do
echo "$host:$result"
done < hostsrc 3< resultsrc
I want to filter out datestamps from the message log and delete all occurances:
(basicly this is a part of an usb history cleaner script, head -n1 added only becouse of testing)
delimiter=`echo $HOSTNAME | cut -f1 -d.`
for item in `egrep usb /var/log/messages | awk -F"$delimiter" '{print $1}' | uniq | head -n1`; do
echo ${item}
done
when I run this command:
egrep usb /var/log/messages | awk -F"$delimiter" '{print $1}' | uniq | head -n1
the output is fine:
Mar 31 03:25:03
but when it will be given back to the for loop, the data transfers like this becouse of the spaces:
Mar
31
03:25:03
the question is: how can I prevent this kind of behaviour?
Instead of:
for item in `whatever`; do
echo ${item}
done
use:
whatever |
while IFS= read -r item; do
echo "${item}"
done
but your whole script could be re-written as just:
awk -F"${HOSTNAME%%.*}" '/usb/ && !seen[$1]++ {print $1}' /var/log/messages
I have the following:
FILENAME=$1
cat $FILENAME | while read LINE
do
response="$LINE" | cut -c1-14
request="$LINE" | cut -c15-31
difference=($response - $request)/1000
echo "$difference"
done
When I run this script it returns blank lines. What am I doing wrong?
Might be simpler in awk:
awk '{print ($1 - $2)/1000}' "$1"
I'm assuming that the first 14 chars and the next 17 chars are the first two blank-separated fields.
You need to change it to:
response=`echo $LINE | cut -c1-14`
request=`echo $LINE | cut -c15-31`
difference=`expr $response - $request`
val=`expr $difference/1000`
You are basically doing everything wrong ;)
This should be better:
FILENAME="$1"
cat "$FILENAME" | while read LINE
do
response=$(echo "$LINE" | cut -c1-14) # or cut -c1-14 <<< "$line"
request=$(echo "$LINE" | cut -c15-31)
difference=$((($response - $request)/1000)
echo "$difference"
done