I want to copy to clipboard something like this
$ command1
$ command2
If you run history you will get the commands in reverse order, so I want to just skip a number of lines from the tail and replace the entry line number with '$'. As you probably suspect this is a very useful shorthand when having to log your workflow or write documentation.
Example:
$ history
1340 pass
1341 pass insert m clouds/cloud9
1342 pass insert -m clouds/cloud9
1343 sudo service docker start
1344 history
So how do you turn that into:
$ sudo service docker start
$ pass insert -m clouds/cloud9
...etc
Assigning $1 works but it will leave a leading space
history | awk '{$1=""; print}'
If you want to copy this to the clipboard, you can use xclip
history | awk '{$1=""; print}' | xclip
Credit goes to https://stackoverflow.com/a/4198169/2032943
maybe you can use these;
history | tac | awk 'NR>1&&NR<=3 {$1="$";print $0}'
tac - concatenate and print files in reverse
NR<=3 : means that the last two commands before history.
NR>1 : to delete history command in history
$1="$" : to replace line numbers to $
test :
$ echo first
first
$ echo second
second
$ history | tac | awk 'NR>1&&NR<=3 {$1="$";print $0}'
$ echo second
$ echo first
Related
I am trying to set up polybar on my newly-installed Arch system. I know very little bash scripting. I am just getting started. If this is not an appropriate question for this forum, I will gladly delete it. I want to get the following awk output in color:
sensors | grep "Package id 0:" | tr -d '+' | awk '{print $4}'"
I know how to do this with echo, so I tried to pass the output so that with the echo command, it would be rendered in color:
sensors | grep "Package id 0:" | tr -d '+' | awk '{print $4}' | echo -e "\e[1;32m ???? \033[0m"
where I want to put the appropriate information where the ??? are.
The awk output is just a temperature, something like this: 50.0°C.
edit: It turns out that there is a very easy way to pass colors to outputs of bash scripts (even python scripts too) in polybar. But I am still stumped as to why the solutions suggested here in the answers work in the terminal but not in the polybar modules. I have several custom modules that use scripts with no problems.
Using awk
$ sensors | awk '/Package id 0:/{gsub(/+/,""); print "\033[32m"$4"\033[0m"}'
If that does not work, you can try this approach;
$ sensors | awk -v color="$(tput setaf 2)" -v end="$(tput sgr0)" '/Package id 0:/{gsub(/+/,""); print color $4 end}'
This is where you want to capture the output of awk. Since awk can do what grep and tr do, I've integrated the pipeline into one awk invocation:
temp=$(sensors | awk '/Package id 0:/ {gsub(/\+/, ""); print $4}')
echo -e "\e[1;32m $temp \033[0m"
I am trying to print all files in /usr/bin/ where the filename starts with a v. This works,
ls -lA /usr/bin/ | awk '{print $9}' | grep ^v
Surprisingly, this returns no output,
ls -lA /usr/bin/ | awk '/^v/ {print $9}'.
I don't understand the difference. I am running Ubuntu 21.10 with awk -W version saying that it is on 1.3.4 20200120.
Edit: I understand that awk may not be the best way to accomplish what I am wanting to do here. But, this is an exercise in learning awk by testing my understanding via comparing it to the real output.
The difference between the two pipelines is that the first outputs the 9th column and then check to see if that starts with a v the second checks to see if the line starts with a v, change the second to:
$ ls -lA /usr/bin/ | awk '$9 ~ /^v/ {print $9}'
When writing:
/pattern/ { ... }
it's the same as writing
$0 ~ /pattern/ { ... }
but in your case you want to compare the 9th column, so write that instead.
But you really don't want to create a pipeline for this, and what would happen if your files contain a space?
You can consider using find or globs instead:
$ printf '%s\n' /usr/bin/v*
/usr/bin/vi
/usr/bin/view
...
or
$ find /usr/bin -name 'v*' -print
/usr/bin/vi
/usr/bin/view
...
Why doesn't this work?
x=5
$ ls -l | awk '{print $(($x))}'
should print field 5 of ls -l command, right?
The only ways you should pass in the value of shell variable to awk are the following
$ x=5
$ ls -l | awk -v x="$x" '{print $x}'
$ ls -l | awk '{print $x}' x="$x"
The main difference between these two methods is that by using -v the value of x is set in the BEGIN block whilst the second method the value would not be set. All other methods with quoting tricks or escaping should not be used unless you like headaches.
However you don't want to being parsing ls at all, the command you really want is:
stat --printf="%s\n" *
Assuming the fifth column of your ls is the same as mine, this will display all the file sizes in the current directory.
You could access the shell variable something similar to these;
The first way is not suggested!
x=5
ls -l | awk '{print $'$x'}'
or assigning the value x to the variable shellVar, before execution of the program begins
x=5
ls -l | awk -v shellVar="$x" '{print $shellVar}'
or using an array containing the values of the current environment
export x=5
ls -l | awk '{print $ENVIRON["x"]}'
That's a shell variable, which is not expanded by the shell in single quotes. The reason we put awk scripts in single quotes is precisely to prevent the shell from interpreting things meant for awk's benefit and screwing things up, but sometimes you want the shell to interpret part of it.
For something like this, I prefer to pass the value in as an awk variable:
ls -l | awk -v "x=$x" '{print $x}'
but you could do any number of other ways. For instance, this:
ls -l | awk '{print $'$x'}'
which should really be this:
ls -l | awk '{print $'"$x"'}'
alternatively, this:
ls -l | awk "{print \$$x}"
Try this :
ls -l | awk '{print $'$x'}'
I am using the following script to get the running process to print the id, command..
if [ "`uname`" = "SunOS" ]
then
awk_c="nawk"
ps_d="/usr/ucb/"
time_parameter=7
else
awk_c="awk"
ps_d=""
time_parameter=5
fi
main_class=RiskEngine
connection_string=db.regression
AWK_CMD='BEGIN{printf "%-15s %-6s %-8s %s\n","ID","PID","STIME","Cmd"} {printf "%-15s %-6s %-8s %s %s %s\n","MY_APP",$2,$time_parameter, main_class, connection_string, port}'
while getopts ":pnh" opt; do
case $opt in
p) AWK_CMD='{ print $2 }'
do_print_message=1;;
n) AWK_CMD='{printf "%-15s %-6s %-8s %s %s %s\n","MY_APP",$2,$time_parameter,main_class, connection_string, port}' ;;
h) print "usage : `basename ${0}` {-p} {-n} : Returns details of process running "
print " -p : Returns a list of PIDS"
print " -n : Returns process list without preceding header"
exit 1 ;
esac
done
ps auxwww | grep $main_class | grep 10348 | grep -v grep | ${awk_c} -v main_class=$merlin_main_class -v connection_string=$merlin_connection_
string -v port=10348 -v time_parameter=$time_parameter "$AWK_CMD"
# cat /etc/redhat-release
Red Hat Enterprise Linux AS release 4 (Nahant Update 6)
# uname -a
Linux deapp25v 2.6.9-67.0.4.EL #1 Fri Jan 18 04:49:54 EST 2008 x86_64 x86_64 x86_64 GNU/Linux
When I am executing the following from the script independently or inside script
# ps auxwww | grep $main_class | grep 10348 | grep -v grep | ${awk_c} -v main_class=$merlin_main_class -v connection_string=$merlin_connection_string -v port=10348 -v time_parameter=$time_parameter "$AWK_CMD"
I get two rows on Linux:
ID PID STIME Cmd
MY_APP 6217 2355352 RiskEngine 10348
MY_APP 21874 5316 RiskEngine 10348
I just have one jvm (Java command) running in the background but still I see 2 rows.
I know one of them (Duplicate with pid 21874) comes from awk command that I am executing. It includes again the main class and the port so two rows. Can you please help me to avoid the one that is duplicate row?
Can you please help me?
AWK can do all that grepping for you.
Here is a simple example of how an AWK command can be selective:
ps auxww | awk -v select="$mainclass" '$0 ~ select && /10348/ && ! (/grep/ || /awk/) && {print}'
ps can be made to selectively output fields which will help a little to reduce false positives. However pgrep may be more useful to you since all you're really using is the PID from the result.
pgrep -f "$mainclass.*10348"
I've reformatted the code as code, but you need to learn that the return key is your friend. The monstrously long pipelines should be split over multiple lines - I typically use one line per command in the pipeline. You can also write awk scripts on more than one line. This makes your code more readable.
Then you need to explain to us what you are up to.
However, it is likely that you are using 'awk' as a variant on grep and are finding that the value 10348 (possibly intended as a port number on some command line) is also in the output of ps as one of the arguments to awk (as is the 'main_class' value), so you get the extra information. You'll need to revise the awk script to eliminate (ignore) the line that contains 'awk'.
Note that you could still be bamboozled by a command running your main class on port 9999 (any value other than 10348) if it so happens that it is run by a process with PID or PPID equal to 10348. If you're going to do the job thoroughly, then the 'awk' script needs to analyze only the 'command plus options' part of the line.
You're already using the grep -v grep trick in your code, why not just update it to exclude the awk process as well with grep -v ${awk_c}?
In other words, the last line of your script would be (on one line and with the real command parameters to awk rather than blah blah blah).:
ps auxwww
| grep $main_class
| grep 10348
| grep -v grep
| grep -v ${awk_c}
| ${awk_c} -v blah blah blah
This will ensure the list of processes will not containg any with the word awk in it.
Keep in mind that it's not always a good idea to do it this way (false positives) but, since you're already taking the risk with processes containing grep, you may as well do so with those containing awk as well.
You can add this simple code in front of all your awk args:
'!/awk/ { .... original awk code .... }'
The '!/awk/' will have the effect of telling awk to ignore any line containing the string awk.
You could also remove your 'grep -v' if you extended my awk suggestion into something like:
'!/awk/ && !/grep/ { ... original awk code ... }'.
I need to copy data from one database into my own database, because i want to run it as a daily cronjob i prefer to have it in bash. I also need to store the values in variables so i can run various checks/validations on the values. This is what i got so far:
echo "SELECT * FROM table WHERE value='ABC' AND value2 IS NULL ORDER BY time" | mysql -u user -h ip db -p | sed 's/\t/,/g' | awk -F, '{print $3,$4,$5,$7 }' > Output
cat Output | while read line
do
Value1=$(awk '{print "",$1}')
Value2=$(awk '{print "",$2}')
Value3=$(awk '{print "",$3}')
Value4=$(awk '{print "",$4}')
echo "INSERT INTO db (value1,value2,value3,value4,value5) VALUES($Value1,$Value2,'$Value3',$Value4,'n')" | mysql -u rb db -p
done
I get the data i need from the database and store it in a new file seperated by spaces. Then i read the file line by line and store the values in variables, and last i run an insert query with the right varables.
I think something goes wrong while storing the values but i cant really figure out what goes wrong.
The awk used to get Value2, Value3 and Value4 does not get the input from $line. You can fix this as:
Value1=$(echo $line | awk '{print $1}')
Value2=$(echo $line | awk '{print $2}')
Value3=$(echo $line | awk '{print $3}')
Value4=$(echo $line | awk '{print $4}')
There's no reason to call awk four times in a loop. That could be very slow. If you don't need the temporary file "Output" for another reason then you don't need it at all - just pipe the output into the while loop. You may not need to use sed to change tabs into commas (you could use tr, by the way) since awk will split fields on tabs (and spaces) by default (unless your data contains spaces, but some of it seems not to).
echo "SELECT * FROM table WHERE value='ABC' AND value2 IS NULL ORDER BY time" |
mysql -u user -h ip db -p |
sed 's/\t/,/g' | # can this be eliminated?
awk -F, '{print $3,$4,$5,$7 }' | # if you eliminate the previous line then omit the -F,
while read line
do
tmparray=($line)
Value1=${tmparray[0]}
Value2=${tmparray[1]}
Value3=${tmparray[2]}
Value4=${tmparray[3]}
echo "INSERT INTO predb (value1,value2,value3,value4,value5) VALUES($Value1,$Value2,'$Value3',$Value4,'n')" | mysql -u rb db -p
done
That uses a temporary array to split the values out of the line. This is another way to do that:
set -- $line
Value1=$1
Value2=$2
Value3=$3
Value4=$4