Shell command with operator followed by pipes - linux

I want a one line command to grab the most recent restart date from JBoss restart logs. I'm currently using the following, which works
ls -rt $JBOSS_HOME/log/ser* |
xargs grep -ih "Incomplete\s*Deploy" |
awk '{print $1" "$2}' | tail -n 1
Now, I want to add an echo if the grep fails to match anything, i.e.:
ls -rt $JBOSS_HOME/log/ser* |
xargs grep -ih "Incomplete\s*Deploy" ||
echo 'NO RESTART' |
awk '{print $1" "$2}' |
tail -n 1
The problem here is that it seems that the OR operator now causes anything following to go with the failed case. How do I specify that I want to OR (echo) to be printed only when the grep fails? When the grep succeeds it should work like the first command I posted.

Use { to group the terms:
ls -rt $JBOSS_HOME/log/ser* |
xargs grep -ih "Incomplete\s*Deploy" && {
awk '{print $1" "$2}' |
tail -n 1
} ||
echo 'NO RESTART'
or as one line:
ls -rt $JBOSS_HOME/log/ser* | xargs grep -ih "Incomplete\s*Deploy" && { awk '{print $1" "$2}' | tail -n 1; } || echo 'NO RESTART'
No additional subshell required.

You can group commands within a pipe by using parentheses:
ls -rt $JBOSS_HOME/log/ser* | ( xargs grep -ih "Incomplete\s*Deploy" || echo 'NO RESTART' ) | awk '{print $1" "$2}' | tail -n 1
This makes the commands in the parentheses run in a subshell, which from the standpoint of the pipe, makes them work as a single command, i.e. they'll take the input and either print the grep match or 'NO RESTART', and then that will be fed into awk.

res=$(ls -rt $JBOSS_HOME/log/ser* | xargs grep -ih "Incomplete\s*Deploy" | awk '{print $1" "$2}' | tail -n 1)
echo "${res:-NO RESTART}"
Also note that this is not safe for filenames with spaces/etc.

Related

grep a word from a list of file as a result of grep before

I have a command to grep a file with fullpath that contain a "TypeId: 0", here is the command
grep -rnw /home/username/app/data/store/0/part/.mv -e "TypeId: 0" | awk -F ":" '{print $1}'
and here is the result:
/home/username/app/data/store/0/part/.mv/521/1673332792072/segmentconfig.yaml /home/username/app/data/store/0/part/.mv/521/1673333077920/segmentconfig.yaml /home/username/app/data/store/0/part/.mv/521/1673333077920/segmentconfig.yaml.old /home/username/app/data/store/0/part/.mv/515/1672993850766/segmentconfig.yaml /home/username/app/data/store/0/part/.mv/515/1672993850766/segmentconfig.yaml.old /home/username/app/data/store/0/part/.mv/703/1672987004847/segmentconfig.yaml /home/username/app/data/store/0/part/.mv/703/1672987004847/segmentconfig.yaml.old
Now I confuse how to grep "numofvertice" from each file from that list.
Anyone have an idea to solve this?
You could try this:
grep -rnw /home/username/app/data/store/0/part/.mv -e "TypeId: 0" | awk -F ":" '{print $1}'|xargs -I{} grep "numofvertice" {}
Like this (GNU grep):
<STDIN> | grep -oP '\b\S+\.yaml' | xargs cat
Or with ack:
cd /home/username/app/data/store/0/part/.mv
ack -wl -e "TypeId: 0" | xargs cat
From ack --help:
-l, --files-with-matches
Only print filenames containing matches

Searching a specific file system in bash

I have a task which asks to write a script which displays all partitions formatted with a specific file system, given as parameter.
I have written the script but when i run it it displays '0'. What am i doing wrong?
This is my code:
#!/bin/bash
n=sudo parted -l | tail -n +8 | awk '{print $5}' | wc | awk '{print $2}'
m=sudo parted -l | tail -n +8 | awk '{print $5}'
q=sudo parted -l | tail -n +8
for i in $n; do
if [ "[ $m | sed -n ip ]" = "$1" ]; then
echo "$q | sed -n ip"
fi
done
Different approach from yours, but does it do what you need?
lsblk -f | awk '$0 ~ fs {print $NF}' fs=ext2

Getting error while running script to find disk space

I am running below script:-
#!/bin/bash
threshold="20"
i=2
result=`df -kh |grep -v “Filesystem” | awk ‘{ print $5 }’ | sed ‘s/%//g’`
for percent in $result; do
if ((percent > threshold))
then
partition=`df -kh | head -$i | tail -1| awk ‘{print $1}’`
echo “$partition at $(hostname -f) is ${percent}% full”
fi
let i=$i+1
done
But I get the following error:
awk: ‘{
awk: ^ invalid char '▒' in expression
sed: -e expression #1, char 1: unknown command: `▒'
Please help me to resolve this.
What awk does not work? (your script does work fine on my Ubuntu)
This line:
result=`df -kh |grep -v "Filesystem" | awk '{ print $5 }' | sed 's/%//g'`
could be changed to:
result=$(df -kh | awk '!/Filesystem/ {print $5+0}')
Avoid using old and outdated backtics if parentheses works like this: var=$(code...)
This:
partition=`df -kh | head -$i | tail -1| awk '{print $1}'`
could be changed to:
partition=$(df -kh | awk -v line="$i" 'NR==line {print $1}')
This
let i=$i+1
could be change to:
((i++))
This would then give some like this:
#!/bin/bash
threshold="20"
i=2
result=$(df -kh | awk '!/Filesystem/ {print $5+0}')
for percent in $result; do
if ((percent > threshold))
then
partition=$(df -kh | awk -v line="$i" 'NR==line {print $1}')
echo "$partition at $(hostname -f) is ${percent}% full"
fi
((i++))
done
You're using ‘ for a single quote not '. Try re-encoding your file with an editor.
You got the answer to your syntax error, now re-write the whole script as just:
#!/bin/bash
df -kh |
awk -v t=20 -v h="$(hostname -f)" '(NR>1)&&($5+0>t){printf "%s at %s is %s full\n",$1,h,$5}'

Use result of pipeline as argument for another command

I'm trying to make part of the output of the first command as another command's argument.
Output of first command is like this, and 3000 is what I want:
XXXXXXXXXXXXX
abcdefg 1020 10:30
[1000] 3000
I extract the pattern by ./command1 | grep '^\[' | awk 'print $2', so it will print out 3000, the value I want.
I'd like to make 3000 as an argument of command2 ./command2 3000. How do I make this work?
command2 $( command1 | awk '/\[/{ print $2 }' )
You can use xargs to pass the input to a new command. In your example you need to include curly braces in your awk argument as well.
./command1 | grep '^\[' | awk '{ print $2 } ' | xargs ./command2
Or more concisely
.command1 | awk '/^\[/ { print $2 }' | xargs ./command2
Example:
echo "[1000] 3000" | awk '/^\[/ { print $2 }' | xargs echo
Output:
3000
There's also sed:
./command1 | sed -n 'n;n;p' | awk '{print $2}'
All together now:
./command2 $(./command1 | sed -n 'n;n;p' | awk '{print $2}') # ./command2 3000
sed will skip 2 lines and print the third.
I would personally try backticks first:
./command2 `./command1 | grep '^\[' | awk 'print $2'`

How to sleep for 1 second between each xargs command?

For example, if I execute
ps aux | awk '{print $1}' | xargs -I {} echo {}
I want to let the shell sleep for 1 second between each echo.
How can I change my shell command?
You can use the following syntax:
ps aux | awk '{print $1}' | xargs -I % sh -c '{ echo %; sleep 1; }'
Be careful with spaces and semicolons though. After every command in between brackets, semicolon is required (even after the last one).
Replace echo by some shell script named sleepecho containing
#!/bin/sh
sleep 1
echo $*
If your awk supports it:
ps aux | awk '{ system("sleep 1"); print $1 }' | xargs -I {} echo {}q
or skip awk and xargs altogether
ps aux | while read -r user rest;
echo $user
sleep 1;
done

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