I paid attention that 'grep' command removes the column names.
I need to customize the output of processes according to the following command:
ps -ef | egrep "java|mysql" | awk {'print $1, $2, $8'}
Regular 'ps' (or even with the 'awk') have column names: UID, PID, etc...
However, when i add 'grep' the column names gone.
Ideally i must have the 'ps' output that displays 4 columns - PID, user name, CMD, and memory usage.
How do i get it preserving the column names.
The grep command will strip the headers because they do not match. Just use awk and match on the first row condition in addition to the search patterns.
ps -ef | awk 'NR==1{print $1,$2,$8} /java|mysql/{print $1, $2, $8}'
Use the power of bash.
$ cat pid_top.sh
#!/bin/bash
echo "Enter String:"
read p
top -n 1 -b -p $(ps -e | grep $p | awk '{print $1}') | tail -n 2
Don't forget chmod +x pid_top.sh
Make an alias or run the script by name, enter a string, e.g. for firefox just fire an you will have and output like this:
$ ./p*
Enter String:
fire
PID USER PR NI VIRT RES SHR S %CPU %MEM ZEIT+ BEFEHL
2983 bang 20 0 1605624 600168 108940 S 0,0 15,1 40:28.10 firefox
Related
mysqladmin proc status | grep "Threads"
Output:
Uptime: 2304 Threads: 14 Questions: 2652099 Slow queries: 0 Opens: 48791 Flush tables: 3 Open tables: 4000 Queries per second avg: 1151.08
I would like to set it so $mysqlthread would output 14 after running echo $mysqlthread
Probably the easiest way is with Perl instead of grep.
mysqladmin proc status | perl -nle'/Threads: (\d+)/ && print $1'
perl -n means "go through each line of input".
perl -l means "print a \n at the end of every print"
perl -e means "here is my program"
/Threads: (\d+)/ means "match Threads: followed by one or more digits. And print $1 means "print the digits I found as denoted by the parentheses around \d+.
Using grep
$ mysqlthread=$(mysqladmin proc status | grep -Po 'Threads: \K\d+')
$ echo "$mysqlthread"
14
There are many ways to solve this. This is one:
mysqladmin proc status | grep "Threads" | tr -s ' ' | cut -d' ' -f4
The tr command with flag -s is used to translate all multiple consecutive spaces into a single space. Then, cut command return the 4th field using a single space as delimiter.
The advantage of piping commands is that one can make this process interactively. And whenever you aren't sure which flag to use, the manual pages are there to help: man grep, man tr, man cut, etc.
Add awk to split the output,
mysqlthread=$(mysqladmin proc status | grep "Threads" | awk '{print $4}')
i'm new to bash scripting and i have to determine if a process is running in a linux environment.
Actually i use the follow command to do the job:
#ps -ef | awk '{print substr($0, index($0,$8))}' | grep -v grep | grep -w -F $PROCESSNAME
where
awk '{print substr($0, index($0,$8))}'
allow me to ignore UID PID PPID C STIME TTY TIME fields and
grep -v grep
allow me to ignore the row that contains the command itself. So at this point i have a list of all processes running on the system.
Finally:
grep -w -F $PROCESSNAME
read a variable which contains the name of the process that i want to check.
For what i understand the full command should return only the row that has the exact value of $PROCESSNAME
Actually this doesn't works correctly for processes that follow the pattern "[processname]", and probably also for other patterns.
For example to simplify, if i have a running process named "[vmmemctl]" and i run:
#ps -ef | grep -v grep | grep -w -F "vmmemctl]"
it actually returns a result:
#root 615 2 0 Feb26 ? 00:01:00 [vmmemctl]
but the actual process name in the command is different from the process name in the result.
What is the correct command that doesn't have this behavior?
Thank you
awk to the rescue!
ps -ef | awk '$8=="[command]"{NF=8;print}'
or
ps -ef | awk -v c="vmmemctl]" '$8==c{NF=8;print}'
note that this is for an exact match not pattern.
since this is an exact match the command can have spaces and other special chars in it (it's not pattern match but string equality). Using your variable name it will look like this
ps -ef | awk -v c="$PROCESSNAME" '$8==c{NF=8;print}'
I need create a shell script to list the process by status type.
The output must be something like:
Process running:
[process]
Process sleeping:
[process]
ETC
I did this, but doesnt work the ps aux | awk '$8 ~ PROCESS':
for PROCESS in `ps -v | awk 'NR!=1 {print $2}' | sort -u`; do
echo "Procesos como $PROCESS:"
ps aux | awk '$8 ~ PROCESS'
done
Cause that script outputs all the process, not filter by Process.
Any help?
A simple solution would be to use ps and sort:
ps u | sort -rk 8
-r reverses the sort (so that the list header remains above), and -k 8 selects the 8th field (STAT).
You can then select processes in a specific state using anything form head to awk, and print out whatever you like.
You can also use top, in non-interactive mode ( the -S option to display and sort by state):
top -b -n 1 -S
an Unix shell script with only purpose - count the number of running processes of qmail (could be anything else). Easy thing, but there must be some bug in code:
#!/bin/bash
rows=`ps aux | grep qmail | wc -l`
echo $rows
Because
echo $rows
always shows greater number of rows (11) than if I just count rows in
ps aux | grep qmail
There are just 8 rows. Does it work this way on your system too?
Nowadays with linux, there is pgrep. If you have it on your system, you can skip grep -v grep
$ var=$(pgrep bash) # or `pgrep bash | wc -l`
$ echo $var
2110 2127 2144 2161 2178 2195 2212 2229
$ set -- $var; echo ${#}
8
also, if your ps command has -C option, another way
$ ps -C bash -o pid= | wc -l
if not, you can set a character class in your grep pattern
$ ps aux|grep [q]mail | wc -l
It appears that you're counting the grep process itself and the header line that ps normally prints before its output.
I'd suggest something more like:
qprocs=$(ps auxwww | grep -c "[q]mail")
... note that GNU grep has a "-c" switch to have it print a "count" of matches rather than the lines themselves. The trick with the regular expression here is to match qmail without matching the literal string that's on the grep command line. So we take any single character in the string and wrap it in square brackets such that it is a single character "class." The regexp: [q]mail matches the string qmail without matching the string [q]mail.
Note that even with this regex you may still find some false positive matches. If you really want to be more precise then you should supply a custom output format string to your ps command (see the man pages) or you should feed it through a pipemill or you should parse the output of the ps command based on fields (using awk or cut or a while read loop). (The -o option to ps is by far the easiest among these).
No, since I'm not running qmail. However, you will want to, at a bare minimum, exclude the process running your grep:
ps aux | grep qmail | grep -v grep
For debugging, you may want to do:
rows=`ps aux | grep qmail`
echo $rows >debug.input
od -xcb debug.input
(to see your input to the script in great detail) and then rewrite your script temporarily as:
#!/bin/bash
rows=`cat debug.input | wc -l`
echo $rows
That way, you can see the input and figure out what effect it's having on your code, even as you debug it.
A good debugger will eventually learn to only change one variable at a time. If your changing your code to get it working, that's the variable - don't let the input to your code change as well.
Use
$ /sbin/pidof qmail
A few ways...
ps -e | grep ' [q]mail' | wc -l
ps -C qmail -opid= | wc -l
pidof qmail | tr ' ' '\n' | wc -l
pgrep is on many Linux distributions, and I imagine available for other Unices.
[dan#khorium ~]$ whatis pgrep
pgrep (1) - look up or signal processes based on name and other attributes
[dan#khorium ~]$ pgrep mingetty
1920
1921
1922
1923
1924
In your case, pgrep qmail | wc -l should do the trick.
I want to do this:
run a command
capture the output
select a line
select a column of that line
Just as an example, let's say I want to get the command name from a $PID (please note this is just an example, I'm not suggesting this is the easiest way to get a command name from a process id - my real problem is with another command whose output format I can't control).
If I run ps I get:
PID TTY TIME CMD
11383 pts/1 00:00:00 bash
11771 pts/1 00:00:00 ps
Now I do ps | egrep 11383 and get
11383 pts/1 00:00:00 bash
Next step: ps | egrep 11383 | cut -d" " -f 4. Output is:
<absolutely nothing/>
The problem is that cut cuts the output by single spaces, and as ps adds some spaces between the 2nd and 3rd columns to keep some resemblance of a table, cut picks an empty string. Of course, I could use cut to select the 7th and not the 4th field, but how can I know, specially when the output is variable and unknown on beforehand.
One easy way is to add a pass of tr to squeeze any repeated field separators out:
$ ps | egrep 11383 | tr -s ' ' | cut -d ' ' -f 4
I think the simplest way is to use awk. Example:
$ echo "11383 pts/1 00:00:00 bash" | awk '{ print $4; }'
bash
Please note that the tr -s ' ' option will not remove any single leading spaces. If your column is right-aligned (as with ps pid)...
$ ps h -o pid,user -C ssh,sshd | tr -s " "
1543 root
19645 root
19731 root
Then cutting will result in a blank line for some of those fields if it is the first column:
$ <previous command> | cut -d ' ' -f1
19645
19731
Unless you precede it with a space, obviously
$ <command> | sed -e "s/.*/ &/" | tr -s " "
Now, for this particular case of pid numbers (not names), there is a function called pgrep:
$ pgrep ssh
Shell functions
However, in general it is actually still possible to use shell functions in a concise manner, because there is a neat thing about the read command:
$ <command> | while read a b; do echo $a; done
The first parameter to read, a, selects the first column, and if there is more, everything else will be put in b. As a result, you never need more variables than the number of your column +1.
So,
while read a b c d; do echo $c; done
will then output the 3rd column. As indicated in my comment...
A piped read will be executed in an environment that does not pass variables to the calling script.
out=$(ps whatever | { read a b c d; echo $c; })
arr=($(ps whatever | { read a b c d; echo $c $b; }))
echo ${arr[1]} # will output 'b'`
The Array Solution
So we then end up with the answer by #frayser which is to use the shell variable IFS which defaults to a space, to split the string into an array. It only works in Bash though. Dash and Ash do not support it. I have had a really hard time splitting a string into components in a Busybox thing. It is easy enough to get a single component (e.g. using awk) and then to repeat that for every parameter you need. But then you end up repeatedly calling awk on the same line, or repeatedly using a read block with echo on the same line. Which is not efficient or pretty. So you end up splitting using ${name%% *} and so on. Makes you yearn for some Python skills because in fact shell scripting is not a lot of fun anymore if half or more of the features you are accustomed to, are gone. But you can assume that even python would not be installed on such a system, and it wasn't ;-).
try
ps |&
while read -p first second third fourth etc ; do
if [[ $first == '11383' ]]
then
echo got: $fourth
fi
done
Your command
ps | egrep 11383 | cut -d" " -f 4
misses a tr -s to squeeze spaces, as unwind explains in his answer.
However, you maybe want to use awk, since it handles all of these actions in a single command:
ps | awk '/11383/ {print $4}'
This prints the 4th column in those lines containing 11383. If you want this to match 11383 if it appears in the beginning of the line, then you can say ps | awk '/^11383/ {print $4}'.
Using array variables
set $(ps | egrep "^11383 "); echo $4
or
A=( $(ps | egrep "^11383 ") ) ; echo ${A[3]}
Similar to brianegge's awk solution, here is the Perl equivalent:
ps | egrep 11383 | perl -lane 'print $F[3]'
-a enables autosplit mode, which populates the #F array with the column data.
Use -F, if your data is comma-delimited, rather than space-delimited.
Field 3 is printed since Perl starts counting from 0 rather than 1
Getting the correct line (example for line no. 6) is done with head and tail and the correct word (word no. 4) can be captured with awk:
command|head -n 6|tail -n 1|awk '{print $4}'
Instead of doing all these greps and stuff, I'd advise you to use ps capabilities of changing output format.
ps -o cmd= -p 12345
You get the cmmand line of a process with the pid specified and nothing else.
This is POSIX-conformant and may be thus considered portable.
Bash's set will parse all output into position parameters.
For instance, with set $(free -h) command, echo $7 will show "Mem:"