Commands by jp (2)

  • Need output in mbps (bits) # ./bytes-second.sh eth0 eth0 interface maximum Speed: 1000Mb/s RX:12883212 TX:17402002 B/s | RX:98 TX:132 Mb/s RX:12371647 TX:17830111 B/s | RX:94 TX:136 Mb/s RX:12502750 TX:17860915 B/s | RX:95 TX:136 Mb/s Show Sample Output


    1
    RX1=`cat /sys/class/net/${INTERFACE}/statistics/rx_bytes` (see script below)
    jp · 2012-01-23 18:22:44 3
  • Need to query hundreds of hosts with an ssh command ? Of course you'll have setup keys on all your remote HOSTs. But in the case a key is not present this command will skip that node, proceeding on to the next. -t: Force pseudo-tty allocation. This can be used to execute arbitrary screen-based programs on a remote machine. Also prevents unwanted stty messages being sent to console -q: Quiet mode. -o "BatchMode yes" If set to yes, passphrase/password querying will be disabled. This option is useful in scripts and other batch jobs where no user is present Show Sample Output


    1
    ssh -tq -o "BatchMode yes" $HOST <some_command> >> to_a_file
    jp · 2011-03-02 20:33:59 0

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List all installed Debian packages
Should work on all systems that use dpkg and APT package management.

Copy 3 files from 3 different servers and adds server name tag to file copied

list files recursively by size

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

find files in a date range
Find files in a specific date range - in this case, the first half of last year. -newermt = modification time of the file is more recent than this date GNU find allows any date specfication that GNU date would accept, e.g. $ find . -type f -newermt "3 years ago" ! -newermt "2 years ago" or $ find . -type f -newermt "last monday"

copy timestamps of files from one location to another - useful when file contents are already synced but timestamps are wrong.
Sometimes when copying files from one place to another, the timestamps get lost. Maybe you forgot to add a flag to preserve timestamps in your copy command. You're sure the files are exactly the same in both locations, but the timestamps of the files in the new home are wrong and you need them to match the source. Using this command, you will get a shell script (/tmp/retime.sh) than you can move to the new location and just execute - it will change the timestamps on all the files and directories to their previous values. Make sure you're in the right directory when you launch it, otherwise all the touch commands will create new zero-length files with those names. Since find's output includes "." it will also change the timestamp of the current directory. Ideally rsync would be the way to handle this - since it only sends changes by default, there would be relatively little network traffic resulting. But rsync has to read the entire file contents on both sides to be sure no bytes have changed, potentially causing a huge amount of local disk I/O on each side. This could be a problem if your files are large. My approach avoids all the comparison I/O. I've seen comments that rsync with the "--size-only" and "--times" options should do this also, but it didn't seem to do what I wanted in my test. With my approach you can review/edit the output commands before running them, so you can tell exactly what will happen. The "tee" command both displays the output on the screen for your review, AND saves it to the file /tmp/retime.sh. Credit: got this idea from Stone's answer at http://serverfault.com/questions/344731/rsync-copying-over-timestamps-only?rq=1, and combined it into one line.

Cleanup firefox's database.

Inverted cowsay
It's quite fun to invert text using "flip.pl" (ref: http://ubuntuforums.org/showthread.php?t=2078323 ). Slightly more challenging is to flip a whole "cowsay". :-)

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Step#2 Create a copy of the bootload and partition table!
Step#2 Create a copy of the bootload and partition table!


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