Commands by fpunktk (10)

  • Print one . instead of each line

    this version only uses shell builtins


    1
    alias ...='while read line; do echo -n "."; done && echo ""'
    fpunktk · 2014-03-17 17:34:19 3
  • a tail function for automatic smart output

    tail() { thbin="/usr/bin/tail"; if [ "${1:0:1}" != "-" ]; then fc=$(($#==0?1:$#)); lpf="$((($LINES - 3 - 2 * $fc) / $fc))"; lpf="$(($lpf<1?2:$lpf))"; [ $fc -eq 1 ] && $thbin -n $lpf "$@" | /usr/bin/fold -w $COLUMNS | $thbin -n $lpf || $thbin -n $lpf "$@"; else $thbin "$@"; fi; unset lpf fc thbin; } This is a function that implements an improved version of tail. It tries to limit the number of lines so that the screen is filled completely. It works with pipes, single and multiple files. If you add different options to tail, they will overwrite the settings from the function. It doesn't work very well when too many files (with wrapped lines) are specified. Its optimised for my three-line prompt. It also works for head. Just s/tail/head/g Don't set 'thbin="tail"', this might lead to a forkbomb.


    -1
    tail() { thbin="/usr/bin/tail"; if [ "${1:0:1}" != "-" ]; then fc=$(($#==0?1:$#)); lpf="$((($LINES - 3 - 2 * $fc) / $fc))"; lpf="$(($lpf<1?2:$lpf))"; [ $fc -eq 1 ] && $thbin -n $lpf "$@" | /usr/bin/fold -w $COLUMNS | $thbin -n $lpf || $thbin -n $lpf...
    fpunktk · 2012-03-23 19:00:30 2
  • diff the outputs of two programs

    I've been looking for this for a long time. Does anybody know how to do this in dash (POSIX shell)? An alternative version might be: exiftool img_1.jpg | diff - <(exiftool img_2.jpg)


    9
    diff <(exiftool img_1.jpg) <(exiftool img_2.jpg)
    fpunktk · 2012-01-30 22:01:17 7
  • add title and alt-text to your collection of xkcd comics

    full command: for fn in xkcd*.png xkcd*.jpg; do; echo $fn; read xw xh <<<$(identify -format '%w %h' $fn); nn="$(echo $fn | sed 's/xkcd-\([0-9]\+\)-.*/\1/')"; wget -q -O xkcd-${nn}.json http://xkcd.com/$nn/info.0.json; tt="$(sed 's/.*"title": "\([^"]*\)", .*/\1/' xkcd-${nn}.json)"; at="$(sed 's/.*alt": "\(.*\)", .*/\1/' xkcd-${nn}.json)"; convert -background white -fill black -font /usr/share/fonts/truetype/freefont/FreeSansBold.ttf -pointsize 26 -size ${xw}x -gravity Center caption:"$tt" tt.png; convert -background '#FFF9BD' -border 1x1 -bordercolor black -fill black -font /usr/share/fonts/truetype/freefont/FreeSans.ttf -pointsize 16 -size $(($xw - 2))x -gravity Center caption:"$at" at.png; th=$(identify -format '%h' tt.png); ah=$(identify -format '%h' at.png); convert -size ${xw}x$(($xh+$th+$ah+5)) "xc:white" tt.png -geometry +0+0 -composite $fn -geometry +0+$th -composite at.png -geometry +0+$(($th+$xh+5)) -composite ${fn%\.*}_cmp.png; echo -e "$fn $nn $xw $xh $th $ah \n$tt \n$at\n"; done this assumes that all comics are saved as xkcd-[number]-[title].{png|jpg}. it will then download the title and alt-text, create pictures from them, and put everything together in a new png-file. it's not perfect, but it worked for nearly all my comics. it uses the xkcd-json-interface. though it's poorly written, it doesn't completely break on http://xkcd.com/859/


    -2
    for fn in xkcd*.png xkcd*.jpg; do echo $fn; read xw xh <<<$(identify -format '%w %h' $fn); nn="$(echo $fn | sed 's/xkcd-\([^-]\+\)-.*/\1/')"; wget -q -O xkcd-${nn}.json http://xkcd.com/$nn/info.0.json; tt="$(sed 's/.*"title": "\([^"]\+\)",.*/\1/' ...
    fpunktk · 2012-01-06 20:26:11 5
  • Command line calculator

    This is an "argument calculator" funktion. The precision is set to 4 and you can use dot (.) or comma (,) as decimal mark (which is great for german users with a comma on the numpad).


    -1
    calc() { echo "scale=4; ${*//,/.}" | bc -l; }
    fpunktk · 2011-10-24 19:58:20 3
  • Command line calculator

    This opens a python command line. You can use math and random and float-division is enabled (without appending .0 to integers). I just don't know how to specify a standard precision.


    1
    python -ic "from __future__ import division; from math import *; from random import *"
    fpunktk · 2011-10-24 19:47:27 4
  • get the oldest file in a directory

    reverse the sorting of ls to get the newest file: ls -1tr --group-directories-first /path/to/dir/ | tail -n 1 Problems: If there are no files in the directory you will get a directory or nothing.


    1
    ls -1t --group-directories-first /path/to/dir/ | tail -n 1
    fpunktk · 2010-12-02 12:25:16 2
  • translate with google, get all translations

    the google-api gives you only one translation which is sometimes insufficent. this function gives you all translations, so you can choose which one fits best.


    1
    translate() { echo $1: $(wget -q -O - 'http://www.google.de/dictionary?source=translation&q='$1'&langpair=en|de' | grep '^<span class="dct-tt">.*</span>$' | sed 's!<span class="dct-tt">\(.*\)</span>!\1, !'); }
    fpunktk · 2010-09-02 00:08:06 2
  • bash-quine

    this command prints itself out. it doesn't need to be stored in a file and it isn't as easy as echo $BASH_COMMAND for information on quines see http://en.wikipedia.org/wiki/Quine_(computing)


    4
    s='s=\47%s\47; printf "$s" "$s"'; printf "$s" "$s"
    fpunktk · 2010-05-09 16:52:58 8
  • delete duplicate lines from a file and keep the order of the other lines

    i wanted to delete all duplicate lines from .bash_history and keep the order of the other lines. the command cat's the file and adds line numbers, then sorts by the second column. afterwards uniq omits repeated lines, but skips the first field (the line number). then it sorts by the line numbers and at the end cuts the numbers off.


    4
    cat -n <file> | sort -k 2 | uniq -f 1 | sort -n | cut -f 2-
    fpunktk · 2010-01-21 18:55:58 8

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Another Matrix Style Implementation
A bit different from some of the other submissions. Has bold and uses all c printable characters. Change the bs=value to speed up and increase the sizes of the bold and non-bold strings.

Give all those pictures the same name format, trailing zeros please for the right order, offset to merge different collections of pictures
When you have different digital cameras, different people, friends and you want to merge all those pictures together, then you get files with same names or files with 3 and 4 digit numbers etc. The result is a mess if you copy it together into one directory. But if you can add an offset to the picture number and set the number of leading zeros in the file name's number then you can manage. OFFS != 0 and LZ the same as the files currently have is not supported. Or left as an exercise, hoho ;) I love NF="${NF/#+(0)/}",it looks like a magic bash spell.

Tar files matching a certain wildcard
This is a shortcut to tar up all files matching a wildcard. Tar doesn't have the --include (apparently).

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

Recursively unrar into dir containing archive
From the cwd, recursively find all rar files, extracting each rar into the directory where it was found, rather than cwd. A nice time saver if you've used wget or similar to mirror something, where each sub dir contains an rar archive. Its likely this can be tuned to work with multi-part archives where all parts use ambiguous .rar extensions but I didn't test this. Perhaps unrar would handle this gracefully anyway?

Limit memory usage per script/program
When I'm testing some scripts or programs, they end up using more memory than anticipated. In that case, computer nearly halts due to swap space usage, and sometimes I have to press Magic SysRq+REISUB to reboot. So, I was looking for a way to limit memory usage per script and found out that ulimit can limit memory. If you run it this way: $ $ ulimit -v 1000000 . $ $ scriptname Then the new memory limit will be valid for that shell. I think changing the limit within a subshell is much more flexible and it won't interfere with your current shell ulimit settings. note: -v 1000000 corresponds to approximately 1GB of RAM

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.

Convert YAML to JSON
Converts YAML file to JSON. Note that you'll need to install PyYAML. Also some YAML data types (like dates) are not supported by JSON).

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"

Download all manuals RedHat 7 (CentOS/Fedora) with one command in Linux

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