Commands by bazzargh (4)

  • NB not 'namei -m .', as it slices the path you give it. Show Sample Output


    16
    namei -m $(pwd)
    bazzargh · 2012-07-24 15:27:20 5
  • Search in decimal rather than hex. od dumps the character list, cut to remove offsets, sort -u gives the used characters. seq gives the comparison list, but we need this sorted alphabetically for comm, which does the filtering. I drop to perl to convert back to characters (is there a better way?) and then use od to dump them in a print-safe format. Show Sample Output


    0
    comm -13 <(od -vw1 -tu1 dummy.txt|cut -c9-|sort -u) <(seq 0 127|sort)|perl -pe '$_=chr($_)'|od -c
    bazzargh · 2012-01-09 01:32:20 7
  • A different approach to the problem - maintain a small sorted list, print the largest as we go, then the top 10 at the end. I often find that the find and sort take a long time, and the large file might appear near the start of the find. By printing as we go, I get better feedback. The sort used in this will be much slower on perls older than 5.8. Show Sample Output


    -2
    find . -type f|perl -lne '@x=sort {$b->[0]<=>$a->[0]}[(stat($_))[7],$_],@x;splice(@x,11);print "@{$x[0]}";END{for(@x){print "@$_"}'
    bazzargh · 2012-01-08 14:43:43 3
  • the output of svn log is annoying to grep, since it spreads the useful info over multiple lines. This compacts the output down to one line so eg you can grep for a comment and see the rev, date & committer straight away. Updated: MUCH shorter, easier to remember. Now it just replaces newlines with spaces, except on '---' lines. Show Sample Output


    1
    svn log | perl -l40pe 's/^-+/\n/'
    bazzargh · 2011-10-14 16:02:22 5

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Happy Days
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du command without showing other mounted file systems

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

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resume other user's screen session via su, without pty error
Normally, if you su to another user from root and try to resume that other user's screen session, you will get an error like "Cannot open your terminal '/dev/pts/0' - please check." This is because the other user doesn't have permission for root's pty. You can get around this by running a "script" session as the new user, before trying to resume the screen session. Note you will have to execute each of the three commands separately, not all on the same line as shown here. Credit: I found this at http://www.hjackson.org/blog/archives/2008/11/29/cannot-open-your-terminal-dev-pts-please-check.

Download SSL server certificate with opsnessl
Useful when we need to create new certificate for site when current one is near expiry. This downloaded cert can be used to provide organisational data directly to new cert. using below command. e.g. openssl x509 -x509toreq -in /tmp/example.com.cert -out example.com.csr -signkey example.com-key.pem

ssh to machine behind shared NAT
Useful to get network access to a machine behind shared IP NAT. Assumes you have an accessible jump host and physical console or drac/ilo/lom etc access to run the command. Run the command on the host behind NAT then ssh connect to your jump host on port 2222. That connection to the jump host will be forwarded to the hidden machine. Note: Some older versions of ssh do not acknowledge the bind address (0.0.0.0 in the example) and will only listen on the loopback address.

Get your external IP address without curl
Curl is not installed by default on many common distros anymore. wget always is :) $ wget -qO- ifconfig.me/ip

Null a file with sudo

power off system in X hours form the current time, here X=2


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