Commands by kostis (3)

  • As an alternative to the above command, this one ditches the unnecessary and complicated for loop in favor of a way faster multi-core approach for a task that's more CPU than I/O intensive, making it a perfect suite for GNU parallel


    4
    parallel cwebp -q 80 {} -o {.}.webp ::: *.png
    kostis · 2018-12-07 23:37:24 1
  • You could have that little benchmark run on all cores in parallel, as a multi-core benchmark or stress test First find the number of cores, then have parallel iterate over that in, well, parallel Show Sample Output


    -1
    time cat /proc/cpuinfo |grep proc|wc -l|xargs seq|parallel -N 0 echo "2^2^20" '|' bc
    kostis · 2018-12-06 05:36:55 0
  • Broken in two parts, first get the number of cores with cat /proc/cpuinfo |grep proc|wc -l and create a integer sequence with that number (xargs seq), then have GNU parallel loop that many times over the given command. Cheers! Show Sample Output


    -2
    time cat /proc/cpuinfo |grep proc|wc -l|xargs seq|parallel -N 0 echo "scale=4000\; a\(1\)\*4" '|' bc -l
    kostis · 2018-12-06 05:15:24 2

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reverse order of file

Email an svn dump
Dumps a compressed svn backup to a file, and emails the files along with any messages as the body of the email

Use the builtin ':' bash command to increment variables
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Changes standard mysql client output to 'less'.
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printf treats first char after single ' as numeric equivalent

Find broken symlinks

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Copy a folder tree through ssh using compression (no temporary files)
This command will copy a folder tree (keeping the parent folders) through ssh. It will: - compress the data - stream the compressed data through ssh - decompress the data on the local folder This command will take no additional space on the host machine (no need to create compressed tar files, transfer it and then delete it on the host). There is some situations (like mirroring a remote machine) where you simply cant wait for a huge time taking scp command or cant compress the data to a tarball on the host because of file system space limitation, so this command can do the job quite well. This command performs very well mainly when a lot of data is involved in the process. If you copying a low amount of data, use scp instead (easier to type)

Server load and process monitoring
In certain cases you mighy need to monitor the server load caused by certain process. For example HTTP, while stress testing apache using ab (apache benchmark) you may want to monitor the server status,load, # of spawned HTTP processes, # of established connections, # of connections in close wait state, apache memory footprint etc.

Show all available colors on your terminal.
Using perl and tput, show all the colors with numbers that your actual $TERM can handle. If want to remove the numbers at beginning of new line, it should be something like this: $perl -E 'say `tput setb $_`," "x `tput cols`, `tput sgr0` for 0 .. (`tput colors` - 1)'


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