How to Capture the Output of a Top Command in a File in Linux

How to capture the output of a top command in a file in linux?

for me top -b > test.txt will store all output from top ok even if i break it with ctrl-c. I suggest you dump first, and then grep the resulting file.

How to capture the output of a top command (for a specific process that will die) in a file

tail -1 does not produce the last line of each screen of output that top produces. It produces only the last line of all the lines.

Try:

top -b -n 1000 -d 5 -p "$MYPID" | grep "$MYPID" > log.txt

This will collect into log.txt all the lines that mention the PID but none of the headers (assuming the PID doesn't appear on a header).

Note that grep is usually buffered. This means that, if you check on log.txt during a run, it might be out of date. With GNU grep, you can keep log.txt up to date with the --line-buffered option:

top -b -n 1000 -d 5 -p "$MYPID" | grep --line-buffered "$MYPID" > log.txt

How To Capture Unix 'Top' Command Output to a CSV file?

If you want to trim runs of whitespace and replace them with commas, try

top -b -n 3 | sed -n '8, 12{s/^ *//;s/ *$//;s/  */,/gp;};12q'

The sed script performs the following substitutions on lines 8 through 12:

• Replace any leading space with nothing (otherwise you get an empty first column when the PID is right-aligned).
• Replace any trailing spaces with nothing (similarly to avoid empty fields after the data).
• Replace any remaining runs of adjacent spaces with a comma. Print this line.

Finally, on line 12, we are done, so we quit sed.

The shell does not pay any attention to the name of the file you are redirecting into and generally, file extensions on Unix are informal decorations, not file type specifiers like they are on some platforms.

You could do echo hello >outputfile.ps and the output would still be text, not PostScript (or a number of other possible interpretations of the .ps file extension). In any event, the echo command does not know that it is being redirected, because that is handled by the shell before the command runs, anyway. (Well, echo is a shell built-in, so in theory there could be some coordination in this case.)

How to redirect output of top command in a file

top -b -n 1 seems to work on my Linux box here (-b: batch mode operation, -n: number of iterations).

Edit:

I just tried it on FreeBSD 9.2 which uses the 3.5beta12 version of top. It seems it needs at least one additional iteration to get CPU stats. So you might want to use:

top -b -d2 -s1 | sed -e '1,/USERNAME/d' | sed -e '1,/^$/d'

-b: batch mode, -d2: 2 displays (the first one does not contain CPU stats, second one does), -s1: wait one seconds between displays

The sed pipeline removes the first display which does not contain CPU stats (by skipping header and process list).

unable to capture top command output in a file using watch command

Managed to write the output of top in a file and add it in cron so that i can get the output in a file after every time interval>>

script:

!/bin/bash

top -b -n 5 -u mysql >> top.txt

crontab entry:

*/1 * * * * cd /scriptpath && sh script.sh

sample output:

top - 17:31:01 up 5 days, 5:59, 3 users, load average: 0.42, 0.38, 0.40
Tasks: 193 total, 1 running, 190 sleeping, 1 stopped, 1 zombie
Cpu(s): 19.6%us, 0.6%sy, 0.0%ni, 78.9%id, 0.3%wa, 0.1%hi, 0.5%si, 0.0%st
Mem: 24686168k total, 24549032k used, 137136k free, 663424k buffers
Swap: 12289716k total, 140k used, 12289576k free, 19292760k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3259 mysql 15 0 3967m 3.5g 6372 S 52.9 14.9 3382:39 mysqld

top - 17:31:04 up 5 days, 5:59, 3 users, load average: 0.47, 0.39, 0.41
Tasks: 192 total, 1 running, 189 sleeping, 1 stopped, 1 zombie
Cpu(s): 4.5%us, 2.5%sy, 0.0%ni, 89.7%id, 0.0%wa, 0.6%hi, 2.8%si, 0.0%st
Mem: 24686168k total, 24549520k used, 136648k free, 663424k buffers
Swap: 12289716k total, 140k used, 12289576k free, 19292772k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3259 mysql 15 0 3967m 3.5g 6372 S 64.1 14.9 3382:41 mysqld

top - 17:31:07 up 5 days, 5:59, 3 users, load average: 0.47, 0.39, 0.41
Tasks: 192 total, 1 running, 189 sleeping, 1 stopped, 1 zombie
Cpu(s): 4.0%us, 1.8%sy, 0.0%ni, 91.7%id, 0.0%wa, 0.5%hi, 2.0%si, 0.0%st
Mem: 24686168k total, 24549256k used, 136912k free, 663428k buffers
Swap: 12289716k total, 140k used, 12289576k free, 19292772k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3259 mysql 15 0 3967m 3.5g 6372 S 56.1 14.9 3382:43 mysqld

top - 17:31:10 up 5 days, 5:59, 3 users, load average: 0.43, 0.39, 0.40
Tasks: 192 total, 1 running, 189 sleeping, 1 stopped, 1 zombie
Cpu(s): 4.0%us, 2.3%sy, 0.0%ni, 90.7%id, 0.0%wa, 0.5%hi, 2.5%si, 0.0%st
Mem: 24686168k total, 24549876k used, 136292k free, 663428k buffers
Swap: 12289716k total, 140k used, 12289576k free, 19292772k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3259 mysql 15 0 3967m 3.5g 6372 S 56.8 14.9 3382:44 mysqld

top - 17:31:13 up 5 days, 5:59, 3 users, load average: 0.40, 0.38, 0.40
Tasks: 192 total, 1 running, 189 sleeping, 1 stopped, 1 zombie
Cpu(s): 4.0%us, 2.1%sy, 0.0%ni, 91.2%id, 0.0%wa, 0.5%hi, 2.2%si, 0.0%st
Mem: 24686168k total, 24549876k used, 136292k free, 663436k buffers
Swap: 12289716k total, 140k used, 12289576k free, 19292772k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3259 mysql 15 0 3967m 3.5g 6372 S 54.8 14.9 3382:46 mysqld

How to get output of top command

Use top in batch mode:

top -bn1 > output.txt

See also this previous answer.

How to correctly save the unix top command output into a variable?

Notice the difference:

#! /bin/bash

x=`top -b -n 1 | head -n 5`
echo $x
echo --------------------
echo "$x"

Output:

top - 14:33:09 up 7 days, 5:58, 4 users, load average: 0.00, 0.00, 0.09 Tasks: 253 total, 2 running, 251 sleeping, 0 stopped, 0 zombie Cpu(s): 1.6%us, 0.4%sy, 70.3%ni, 27.6%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 3926784k total, 3644624k used, 282160k free, 232696k buffers Swap: 9936160k total, 101156k used, 9835004k free, 1287352k cached
--------------------
top - 14:33:09 up 7 days,  5:58,  4 users,  load average: 0.00, 0.00, 0.09
Tasks: 253 total,   2 running, 251 sleeping,   0 stopped,   0 zombie
Cpu(s):  1.6%us,  0.4%sy, 70.3%ni, 27.6%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:   3926784k total,  3644624k used,   282160k free,   232696k buffers
Swap:  9936160k total,   101156k used,  9835004k free,  1287352k cached

Without the quotes, the contents of the variable are ground up in the shell's argument processing.

python script to capture output of top command

Since you're waiting for the process to finish, you need to tell top to only print its output once, and then quit.

You can do that by running:

top -n 1

Getting the first 5 lines from PID and COMMAND using top

With your shown samples, please try following code. Since you need top 5 PIDs details so printing first 5 lines wouldn't work here. So skipping first 6 lines in output of top(which are about system details).

top -b | awk 'FNR>=7 && FNR<=12{print $1};FNR==12{exit}'

Explanation: Simple explanation of above code would be, passing top command's output to awk as an standard input. Then in awk program checking condition if line number is from 7th to 12th then print it and on 12th line exit out of program.

Where definition of top -b option is as follows from man top:

b :Batch-mode operation Starts top in Batch mode, which could be
useful for sending output from top to other programs or to a file. In
this mode, top will not accept input and runs until the iterations
limit you've set with the `-n' command-line option or until killed.

Capture %CPU and PID of processes filtered by COMMAND using top command

Awk can do this; awk '/regex/ { print }' performs the print action only on lines matching regex.

However, you can (and perhaps also should) subsume head and tail as well:

top -b -n 1 | awk 'NR>1 && $10 == "chrome" {print strftime("%T"), $1, $9}' 

... assuming the tenth field of top output contains the command name.

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