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Homemade / homebrew HF transceivers

Homebrew transceivers by radio amateurs. Some of these are high performance transceivers, even they are homemade.

Keywords: homebrew hf, radio transceiver, homebrew ssb, homemade hf, homebrew vfo, homemade vfo, digital DDS, transceivers, homebrew hf transceiver, DDS VFO, ssb transceiver, homemade, hamradio, amateur radio, SSB, band, Single Sideband, USB, LSB, CW, receiver, transmitter, exciter, power amplifier, bandpass filter, automatic gain control (AGC), cw 80, ssb radio, homebrewing, QRP SSB transceiver, QRP CW, transceiver qrp, build ssb transceiver, 3.5mhz transceiver, HF all band SSB-CW, transceiver schematic, homemade hamradio.

Homemade HF transceivers:



HF multi-band transceivers (homebrew)


visit dxzone - click here
Visit DXZone – Technical Reference – Ham Radio homebrew and home-made


The HF all-band homebrew transceiver by jg1ead

The home made transceiver covers 3.5 to 3.6 MHz and is CW only. It has the following features:

Characteristics and composition:

  • Frequency coverage : 3.5MHz-28MHz 8band
  • Mode : SSB/CW
  • TX-final : 2SC1947
  • Power output : 1W
  • RX-RF amp : 2SK125*2(Grounded Gates)
  • 1stIF : 48.7265MHz
  • TX/RX 1st mixer : MiniCircuit MCL-1
  • RX 1st IF amp : MC1350P
  • 2ndIF : 11.2735MHz
  • TX/RX 2nd mixer : MiniCircuit MCL-1
  • RX-2nd IF : MC1350P*2

Circuit schematic of the local oscillator unit
80m transceiver site panel

Schematics diagram are available: homebrew transceiver


T03DSP High Performance Transceiver with DSP IF processing

T03DSP transceiver

The goal of this project was to build a high performance HF transceiver with DSP IF processing. I did not try to archive as high parameters as possible, I just tried to get most from the available technology (i.e. mechanical and electrical parts and assembly technology). I tried to keep the design as simple as possible. The design widely uses “software” techniques that allows easy modifications and opens new possibilities.

Features

  • Amateur radio bands (160m,80m,40m,30m,20m,17m,15m,12m,10m)
  • 0.25 Hz and more (two tuning speed for each mode is available), implemented adaptive tuning step (1x..20x)
  • USB, LSB, CW (Normal/Reverse), AFSK, RTTY (decode only by now), (PSK31 with decoder and coder will be implemented in software later)
  • Selectivity 100Hz-3000Hz bandwidth in 50Hz steps
  • Automatic memory keyer (built in)
  • Automatic contest number generation, 5 different number formats available
  • Digital RX:S-meter and calibrated input signal power meter
  • Digital TX:Output power, SWR and compression (displayed simultaneously)
  • 24h real time clock (powered from ionistor during power off periods)
  • AFC and tuning indicator in RTTY mode
  • Adjustable voice operated squelch for SSB mode
  • CAT system compatible with Kenwood command set
  • Built in dual tone generator for transmitter testing

T03DSP audio amlifier

T03DSP audio amlifier

Transceiver DSP

Transceiver DSP

Transceiver display

Transceiver display
Transceiver display
Transceiver display
Transceiver display
Transceiver display
Transceiver display
Transceiver display

Schematics diagram are available: High Performance Transceiver

Read More..

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Homemade / homebrew HF transceivers

Homebrew transceivers by radio amateurs. Some of these are high performance transceivers, even they are homemade.

Keywords: homebrew hf, radio transceiver, homebrew ssb, homemade hf, homebrew vfo, homemade vfo, digital DDS, transceivers, homebrew hf transceiver, DDS VFO, ssb transceiver, homemade, hamradio, amateur radio, SSB, band, Single Sideband, USB, LSB, CW, receiver, transmitter, exciter, power amplifier, bandpass filter, automatic gain control (AGC), cw 80, ssb radio, homebrewing, QRP SSB transceiver, QRP CW, transceiver qrp, build ssb transceiver, 3.5mhz transceiver, HF all band SSB-CW, transceiver schematic, homemade hamradio.

Homemade HF transceivers:



HF multi-band transceivers (homebrew)


visit dxzone - click here
Visit DXZone – Technical Reference – Ham Radio homebrew and home-made


The HF all-band homebrew transceiver by jg1ead

The home made transceiver covers 3.5 to 3.6 MHz and is CW only. It has the following features:

Characteristics and composition:

  • Frequency coverage : 3.5MHz-28MHz 8band
  • Mode : SSB/CW
  • TX-final : 2SC1947
  • Power output : 1W
  • RX-RF amp : 2SK125*2(Grounded Gates)
  • 1stIF : 48.7265MHz
  • TX/RX 1st mixer : MiniCircuit MCL-1
  • RX 1st IF amp : MC1350P
  • 2ndIF : 11.2735MHz
  • TX/RX 2nd mixer : MiniCircuit MCL-1
  • RX-2nd IF : MC1350P*2

Circuit schematic of the local oscillator unit
80m transceiver site panel

Schematics diagram are available: homebrew transceiver


T03DSP High Performance Transceiver with DSP IF processing

T03DSP transceiver

The goal of this project was to build a high performance HF transceiver with DSP IF processing. I did not try to archive as high parameters as possible, I just tried to get most from the available technology (i.e. mechanical and electrical parts and assembly technology). I tried to keep the design as simple as possible. The design widely uses “software” techniques that allows easy modifications and opens new possibilities.

Features

  • Amateur radio bands (160m,80m,40m,30m,20m,17m,15m,12m,10m)
  • 0.25 Hz and more (two tuning speed for each mode is available), implemented adaptive tuning step (1x..20x)
  • USB, LSB, CW (Normal/Reverse), AFSK, RTTY (decode only by now), (PSK31 with decoder and coder will be implemented in software later)
  • Selectivity 100Hz-3000Hz bandwidth in 50Hz steps
  • Automatic memory keyer (built in)
  • Automatic contest number generation, 5 different number formats available
  • Digital RX:S-meter and calibrated input signal power meter
  • Digital TX:Output power, SWR and compression (displayed simultaneously)
  • 24h real time clock (powered from ionistor during power off periods)
  • AFC and tuning indicator in RTTY mode
  • Adjustable voice operated squelch for SSB mode
  • CAT system compatible with Kenwood command set
  • Built in dual tone generator for transmitter testing

T03DSP audio amlifier

T03DSP audio amlifier

Transceiver DSP

Transceiver DSP

Transceiver display

Transceiver display
Transceiver display
Transceiver display
Transceiver display
Transceiver display
Transceiver display
Transceiver display

Schematics diagram are available: High Performance Transceiver

Read More..

A $1.00 Noise Reducing Speaker

Many a good QSO has been wrecked by that high pitched crackling noise that is common on weak
signals. Sometimes it comes in louder than the voice and makes it impossible for you to hear your
partner. It’s called “Bacon Frying” or “Spike Noise” and it’s the enemy of every ham.

Spike noise is a high frequency pulse that rides on top of the voice on weak signals. It is usually the
highest pitched sound coming from your speaker and sometimes it’s the loudest. Traditionally this
has been handled by add on filtering systems using either analog or digital signal processing
methods. Only high end (i.e. expensive) rigs have had these devices built in. Whether analog or
digital, many low end and mobile radios don’t include them.
Fear not! There is a perfectly workable solution to the problem using nothing more than a couple of
cheap parts…

The circuit, pictured below, is a simple low pass filter that can be added to any speaker and uses
only a pair of 50 cent parts.

noise reduction speaker 300x109 A $1.00 Noise Reducing Speaker

Despite the unusual electronic symbol, C1 is a common non-polarized electrolytic capacitor used
mostly in speaker crossover networks. It has to be non-polarized because the speaker is working on
alternating current. You cannot use a polarized electrolytic capacitor here because under reverse
voltage it acts like a short and would cause considerable distortion.
The resistor, R1, is also a common part you can get at any electronics supply house. There is some
volume loss due to the resistor being in series with one of the speaker leads but it is barely
noticeable and given the benefits, it’s a good trade off.
Human speech doesn’t require full fidelity audio. Most voice energy is concentrated in the range of
400 to 3000 hz. Most of the really annoying noise is in the range of 2500 to 10,000 hz. Since these
two ranges don’t overlap very much we can effectively reduce the audible noise on a signal using a
low pass filter to remove the portion of the audio spectrum above 3,000hz. This effectively takes off
the noise and leaves the voice alone.
The combination of series resistor and shunt capacitor forms our low pass filter. At low frequencies
the capacitor appears as an open circuit and all the audio goes to the speaker. At higher frequencies
it acts as a short across the speaker, causing this energy to be dissipated across the resistor where
we don’t hear it.
The part values for noise canceling with minimal impact on voice quality are on the right. The
resistor should be 2 watts or better. The capacitor should be a non-polarized electrolytic type rated
for at least 16 volts.
There is no harm in experimenting with different capacitor values to get a tonality you like.
Increasing the capacitor’s value will increase the noise reduction but will also make voices sound
more bassy. Go too far and everything will sound muffled. To avoid excessive losses you should
always match the resistor with the impedance of your speaker.

Wire wound resistors work better in that situation than carbon ones… the inductance of the wire coil helps the curve of the filter.

noise reduction speaker values 300x209 A $1.00 Noise Reducing Speaker

Ok, a $1.00 circuit isn’t going to replace a $100.00 DSP unit but it can bring about considerable
relief from that nasty crackling noise and it might save you a couple of headaches when trying to
work that rare signal. So there you have it… less than a dollar for a noise reducing speaker that will
turn your station into a headache free zone!

An article by L.D. Blake – VE3VDC

Ham radio logger program for linux

The world best Linux ham radio logger program

Ham radio maps

romania ham radio prefix map 300x203 Ham radio maps

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DX-spots

Amateur radio list of HF Beacons

Amateur radio wire antenna SWR table

Amateur radio wire antenna SWR table

Use this balun for the antenna:
balun1 9 Amateur radio wire antenna SWR table

Multiple search and replace in a file

Sometime we have to change a file by searching and replacing words on it.
But if we have too many search/replace pairs that is a huge work.
I’ve created a bash/shell script to which will do it automatically the replace. You can run it on Linux terminal.

This is the shell script file_replace.sh:

#!/bin/bash
#in terminal: chmod 777 file_replace.sh
for cur_line in `cat file_replace_data.txt`; do
    if [ "$(echo $cur_line | grep -o ',')" ] && [ "${cur_line:0:1}" ]; then #test if the line contain a ,
        search=$(echo $cur_line | cut -d "," -f 1) #get the search string
        replace=$(echo $cur_line | cut -d "," -f 2) #get the replace string
        sed -i 's/'$search'/'$replace'/i' file_replace_text.txt #replace the string in the file
    fi
done

You have to have a file file_replace_data.txt containing your test, a file with search/replace words file_replace_data.txt, every line contain search word, a separator and the replace word

apple,beer
potatoes,wine

So apple will be replaced with beer and potatoes with wine.

One line sed

FILE SPACING:

 # double space a file
 sed G

 # double space a file which already has blank lines in it. Output file
 # should contain no more than one blank line between lines of text.
 sed '/^$/d;G'

 # triple space a file
 sed 'G;G'

 # undo double-spacing (assumes even-numbered lines are always blank)
 sed 'n;d'

 # insert a blank line above every line which matches "regex"
 sed '/regex/{x;p;x;}'

 # insert a blank line below every line which matches "regex"
 sed '/regex/G'

 # insert a blank line above and below every line which matches "regex"
 sed '/regex/{x;p;x;G;}'

NUMBERING:

 # number each line of a file (simple left alignment). Using a tab (see
 # note on '\t' at end of file) instead of space will preserve margins.
 sed = filename | sed 'N;s/\n/\t/'

 # number each line of a file (number on left, right-aligned)
 sed = filename | sed 'N; s/^/     /; s/ *\(.\{6,\}\)\n/\1  /'

 # number each line of file, but only print numbers if line is not blank
 sed '/./=' filename | sed '/./N; s/\n/ /'

 # count lines (emulates "wc -l")
 sed -n '$='

TEXT CONVERSION AND SUBSTITUTION:

 # IN UNIX ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format.
 sed 's/.$//'               # assumes that all lines end with CR/LF
 sed 's/^M$//'              # in bash/tcsh, press Ctrl-V then Ctrl-M
 sed 's/\x0D$//'            # works on ssed, gsed 3.02.80 or higher

 # IN UNIX ENVIRONMENT: convert Unix newlines (LF) to DOS format.
 sed "s/$/`echo -e \\\r`/"            # command line under ksh
 sed 's/$'"/`echo \\\r`/"             # command line under bash
 sed "s/$/`echo \\\r`/"               # command line under zsh
 sed 's/$/\r/'                        # gsed 3.02.80 or higher

 # IN DOS ENVIRONMENT: convert Unix newlines (LF) to DOS format.
 sed "s/$//"                          # method 1
 sed -n p                             # method 2

 # IN DOS ENVIRONMENT: convert DOS newlines (CR/LF) to Unix format.
 # Can only be done with UnxUtils sed, version 4.0.7 or higher. The
 # UnxUtils version can be identified by the custom "--text" switch
 # which appears when you use the "--help" switch. Otherwise, changing
 # DOS newlines to Unix newlines cannot be done with sed in a DOS
 # environment. Use "tr" instead.
 sed "s/\r//" infile >outfile         # UnxUtils sed v4.0.7 or higher
 tr -d \r outfile            # GNU tr version 1.22 or higher

 # delete leading whitespace (spaces, tabs) from front of each line
 # aligns all text flush left
 sed 's/^[ \t]*//'                    # see note on '\t' at end of file

 # delete trailing whitespace (spaces, tabs) from end of each line
 sed 's/[ \t]*$//'                    # see note on '\t' at end of file

 # delete BOTH leading and trailing whitespace from each line
 sed 's/^[ \t]*//;s/[ \t]*$//'

 # insert 5 blank spaces at beginning of each line (make page offset)
 sed 's/^/     /'

 # align all text flush right on a 79-column width
 sed -e :a -e 's/^.\{1,78\}$/ &/;ta'  # set at 78 plus 1 space

 # center all text in the middle of 79-column width. In method 1,
 # spaces at the beginning of the line are significant, and trailing
 # spaces are appended at the end of the line. In method 2, spaces at
 # the beginning of the line are discarded in centering the line, and
 # no trailing spaces appear at the end of lines.
 sed  -e :a -e 's/^.\{1,77\}$/ & /;ta'                     # method 1
 sed  -e :a -e 's/^.\{1,77\}$/ &/;ta' -e 's/\( *\)\1/\1/'  # method 2

 # substitute (find and replace) "foo" with "bar" on each line
 sed 's/foo/bar/'             # replaces only 1st instance in a line
 sed 's/foo/bar/4'            # replaces only 4th instance in a line
 sed 's/foo/bar/g'            # replaces ALL instances in a line
 sed 's/\(.*\)foo\(.*foo\)/\1bar\2/' # replace the next-to-last case
 sed 's/\(.*\)foo/\1bar/'            # replace only the last case

 # substitute "foo" with "bar" ONLY for lines which contain "baz"
 sed '/baz/s/foo/bar/g'

 # substitute "foo" with "bar" EXCEPT for lines which contain "baz"
 sed '/baz/!s/foo/bar/g'

 # change "scarlet" or "ruby" or "puce" to "red"
 sed 's/scarlet/red/g;s/ruby/red/g;s/puce/red/g'   # most seds
 gsed 's/scarlet\|ruby\|puce/red/g'                # GNU sed only

 # reverse order of lines (emulates "tac")
 # bug/feature in HHsed v1.5 causes blank lines to be deleted
 sed '1!G;h;$!d'               # method 1
 sed -n '1!G;h;$p'             # method 2

 # reverse each character on the line (emulates "rev")
 sed '/\n/!G;s/\(.\)\(.*\n\)/&\2\1/;//D;s/.//'

 # join pairs of lines side-by-side (like "paste")
 sed '$!N;s/\n/ /'

 # if a line ends with a backslash, append the next line to it
 sed -e :a -e '/\\$/N; s/\\\n//; ta'

 # if a line begins with an equal sign, append it to the previous line
 # and replace the "=" with a single space
 sed -e :a -e '$!N;s/\n=/ /;ta' -e 'P;D'

 # add commas to numeric strings, changing "1234567" to "1,234,567"
 gsed ':a;s/\B[0-9]\{3\}\>/,&/;ta'                     # GNU sed
 sed -e :a -e 's/\(.*[0-9]\)\([0-9]\{3\}\)/\1,\2/;ta'  # other seds

 # add commas to numbers with decimal points and minus signs (GNU sed)
 gsed -r ':a;s/(^|[^0-9.])([0-9]+)([0-9]{3})/\1\2,\3/g;ta'

 # add a blank line every 5 lines (after lines 5, 10, 15, 20, etc.)
 gsed '0~5G'                  # GNU sed only
 sed 'n;n;n;n;G;'             # other seds

SELECTIVE PRINTING OF CERTAIN LINES:

 # print first 10 lines of file (emulates behavior of "head")
 sed 10q

 # print first line of file (emulates "head -1")
 sed q

 # print the last 10 lines of a file (emulates "tail")
 sed -e :a -e '$q;N;11,$D;ba'

 # print the last 2 lines of a file (emulates "tail -2")
 sed '$!N;$!D'

 # print the last line of a file (emulates "tail -1")
 sed '$!d'                    # method 1
 sed -n '$p'                  # method 2

 # print the next-to-the-last line of a file
 sed -e '$!{h;d;}' -e x              # for 1-line files, print blank line
 sed -e '1{$q;}' -e '$!{h;d;}' -e x  # for 1-line files, print the line
 sed -e '1{$d;}' -e '$!{h;d;}' -e x  # for 1-line files, print nothing

 # print only lines which match regular expression (emulates "grep")
 sed -n '/regexp/p'           # method 1
 sed '/regexp/!d'             # method 2

 # print only lines which do NOT match regexp (emulates "grep -v")
 sed -n '/regexp/!p'          # method 1, corresponds to above
 sed '/regexp/d'              # method 2, simpler syntax

 # print the line immediately before a regexp, but not the line
 # containing the regexp
 sed -n '/regexp/{g;1!p;};h'

 # print the line immediately after a regexp, but not the line
 # containing the regexp
 sed -n '/regexp/{n;p;}'

 # print 1 line of context before and after regexp, with line number
 # indicating where the regexp occurred (similar to "grep -A1 -B1")
 sed -n -e '/regexp/{=;x;1!p;g;$!N;p;D;}' -e h

 # grep for AAA and BBB and CCC (in any order)
 sed '/AAA/!d; /BBB/!d; /CCC/!d'

 # grep for AAA and BBB and CCC (in that order)
 sed '/AAA.*BBB.*CCC/!d'

 # grep for AAA or BBB or CCC (emulates "egrep")
 sed -e '/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d    # most seds
 gsed '/AAA\|BBB\|CCC/!d'                        # GNU sed only

 # print paragraph if it contains AAA (blank lines separate paragraphs)
 # HHsed v1.5 must insert a 'G;' after 'x;' in the next 3 scripts below
 sed -e '/./{H;$!d;}' -e 'x;/AAA/!d;'

 # print paragraph if it contains AAA and BBB and CCC (in any order)
 sed -e '/./{H;$!d;}' -e 'x;/AAA/!d;/BBB/!d;/CCC/!d'

 # print paragraph if it contains AAA or BBB or CCC
 sed -e '/./{H;$!d;}' -e 'x;/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d
 gsed '/./{H;$!d;};x;/AAA\|BBB\|CCC/b;d'         # GNU sed only

 # print only lines of 65 characters or longer
 sed -n '/^.\{65\}/p'

 # print only lines of less than 65 characters
 sed -n '/^.\{65\}/!p'        # method 1, corresponds to above
 sed '/^.\{65\}/d'            # method 2, simpler syntax

 # print section of file from regular expression to end of file
 sed -n '/regexp/,$p'

 # print section of file based on line numbers (lines 8-12, inclusive)
 sed -n '8,12p'               # method 1
 sed '8,12!d'                 # method 2

 # print line number 52
 sed -n '52p'                 # method 1
 sed '52!d'                   # method 2
 sed '52q;d'                  # method 3, efficient on large files

 # beginning at line 3, print every 7th line
 gsed -n '3~7p'               # GNU sed only
 sed -n '3,${p;n;n;n;n;n;n;}' # other seds

 # print section of file between two regular expressions (inclusive)
 sed -n '/Iowa/,/Montana/p'             # case sensitive

SELECTIVE DELETION OF CERTAIN LINES:

 # print all of file EXCEPT section between 2 regular expressions
 sed '/Iowa/,/Montana/d'

 # delete duplicate, consecutive lines from a file (emulates "uniq").
 # First line in a set of duplicate lines is kept, rest are deleted.
 sed '$!N; /^\(.*\)\n\1$/!P; D'

 # delete duplicate, nonconsecutive lines from a file. Beware not to
 # overflow the buffer size of the hold space, or else use GNU sed.
 sed -n 'G; s/\n/&&/; /^\([ -~]*\n\).*\n\1/d; s/\n//; h; P'

 # delete all lines except duplicate lines (emulates "uniq -d").
 sed '$!N; s/^\(.*\)\n\1$/\1/; t; D'

 # delete the first 10 lines of a file
 sed '1,10d'

 # delete the last line of a file
 sed '$d'

 # delete the last 2 lines of a file
 sed 'N;$!P;$!D;$d'

 # delete the last 10 lines of a file
 sed -e :a -e '$d;N;2,10ba' -e 'P;D'   # method 1
 sed -n -e :a -e '1,10!{P;N;D;};N;ba'  # method 2

 # delete every 8th line
 gsed '0~8d'                           # GNU sed only
 sed 'n;n;n;n;n;n;n;d;'                # other seds

 # delete lines matching pattern
 sed '/pattern/d'

 # delete ALL blank lines from a file (same as "grep '.' ")
 sed '/^$/d'                           # method 1
 sed '/./!d'                           # method 2

 # delete all CONSECUTIVE blank lines from file except the first; also
 # deletes all blank lines from top and end of file (emulates "cat -s")
 sed '/./,/^$/!d'          # method 1, allows 0 blanks at top, 1 at EOF
 sed '/^$/N;/\n$/D'        # method 2, allows 1 blank at top, 0 at EOF

 # delete all CONSECUTIVE blank lines from file except the first 2:
 sed '/^$/N;/\n$/N;//D'

 # delete all leading blank lines at top of file
 sed '/./,$!d'

 # delete all trailing blank lines at end of file
 sed -e :a -e '/^\n*$/{$d;N;ba' -e '}'  # works on all seds
 sed -e :a -e '/^\n*$/N;/\n$/ba'        # ditto, except for gsed 3.02.*

 # delete the last line of each paragraph
 sed -n '/^$/{p;h;};/./{x;/./p;}'

SPECIAL APPLICATIONS:

 # remove nroff overstrikes (char, backspace) from man pages. The 'echo'
 # command may need an -e switch if you use Unix System V or bash shell.
 sed "s/.`echo \\\b`//g"    # double quotes required for Unix environment
 sed 's/.^H//g'             # in bash/tcsh, press Ctrl-V and then Ctrl-H
 sed 's/.\x08//g'           # hex expression for sed 1.5, GNU sed, ssed

 # get Usenet/e-mail message header
 sed '/^$/q'                # deletes everything after first blank line

 # get Usenet/e-mail message body
 sed '1,/^$/d'              # deletes everything up to first blank line

 # get Subject header, but remove initial "Subject: " portion
 sed '/^Subject: */!d; s///;q'

 # get return address header
 sed '/^Reply-To:/q; /^From:/h; /./d;g;q'

 # parse out the address proper. Pulls out the e-mail address by itself
 # from the 1-line return address header (see preceding script)
 sed 's/ *(.*)//; s/>.*//; s/.*[:<] *//'

 # add a leading angle bracket and space to each line (quote a message)
 sed 's/^/> /'

 # delete leading angle bracket & space from each line (unquote a message)
 sed 's/^> //'

 # remove most HTML tags (accommodates multiple-line tags)
 sed -e :a -e 's/<[^>]*>//g;/zipup.bat
 dir /b *.txt | sed "s/^\(.*\)\.TXT/pkzip -mo \1 \1.TXT/" >>zipup.bat

TYPICAL USE: Sed takes one or more editing commands and applies all of
them, in sequence, to each line of input. After all the commands have
been applied to the first input line, that line is output and a second
input line is taken for processing, and the cycle repeats. The
preceding examples assume that input comes from the standard input
device (i.e, the console, normally this will be piped input). One or
more filenames can be appended to the command line if the input does
not come from stdin. Output is sent to stdout (the screen). Thus:

 cat filename | sed '10q'        # uses piped input
 sed '10q' filename              # same effect, avoids a useless "cat"
 sed '10q' filename > newfile    # redirects output to disk

For additional syntax instructions, including the way to apply editing
commands from a disk file instead of the command line, consult "sed &
awk, 2nd Edition," by Dale Dougherty and Arnold Robbins (O'Reilly,
1997; http://www.ora.com), "UNIX Text Processing," by Dale Dougherty
and Tim O'Reilly (Hayden Books, 1987) or the tutorials by Mike Arst
distributed in U-SEDIT2.ZIP (many sites). To fully exploit the power
of sed, one must understand "regular expressions." For this, see
"Mastering Regular Expressions" by Jeffrey Friedl (O'Reilly, 1997).
The manual ("man") pages on Unix systems may be helpful (try "man
sed", "man regexp", or the subsection on regular expressions in "man
ed"), but man pages are notoriously difficult. They are not written to
teach sed use or regexps to first-time users, but as a reference text
for those already acquainted with these tools.

QUOTING SYNTAX: The preceding examples use single quotes ('...')
instead of double quotes ("...") to enclose editing commands, since
sed is typically used on a Unix platform. Single quotes prevent the
Unix shell from intrepreting the dollar sign ($) and backquotes
(`...`), which are expanded by the shell if they are enclosed in
double quotes. Users of the "csh" shell and derivatives will also need
to quote the exclamation mark (!) with the backslash (i.e., \!) to
properly run the examples listed above, even within single quotes.
Versions of sed written for DOS invariably require double quotes
("...") instead of single quotes to enclose editing commands.

USE OF '\t' IN SED SCRIPTS: For clarity in documentation, we have used
the expression '\t' to indicate a tab character (0x09) in the scripts.
However, most versions of sed do not recognize the '\t' abbreviation,
so when typing these scripts from the command line, you should press
the TAB key instead. '\t' is supported as a regular expression
metacharacter in awk, perl, and HHsed, sedmod, and GNU sed v3.02.80.

VERSIONS OF SED: Versions of sed do differ, and some slight syntax
variation is to be expected. In particular, most do not support the
use of labels (:name) or branch instructions (b,t) within editing
commands, except at the end of those commands. We have used the syntax
which will be portable to most users of sed, even though the popular
GNU versions of sed allow a more succinct syntax. When the reader sees
a fairly long command such as this:

   sed -e '/AAA/b' -e '/BBB/b' -e '/CCC/b' -e d

it is heartening to know that GNU sed will let you reduce it to:

   sed '/AAA/b;/BBB/b;/CCC/b;d'      # or even
   sed '/AAA\|BBB\|CCC/b;d'

In addition, remember that while many versions of sed accept a command
like "/one/ s/RE1/RE2/", some do NOT allow "/one/! s/RE1/RE2/", which
contains space before the 's'. Omit the space when typing the command.

OPTIMIZING FOR SPEED: If execution speed needs to be increased (due to
large input files or slow processors or hard disks), substitution will
be executed more quickly if the "find" expression is specified before
giving the "s/.../.../" instruction. Thus:

   sed 's/foo/bar/g' filename         # standard replace command
   sed '/foo/ s/foo/bar/g' filename   # executes more quickly
   sed '/foo/ s//bar/g' filename      # shorthand sed syntax

On line selection or deletion in which you only need to output lines
from the first part of the file, a "quit" command (q) in the script
will drastically reduce processing time for large files. Thus:

   sed -n '45,50p' filename           # print line nos. 45-50 of a file
   sed -n '51q;45,50p' filename       # same, but executes much faster

Generate random number

On Linux we can use /dev/random to generate a random number.

od -An -N2 -i /dev/random

To generate a random number named temporary file we use touch command:

touch `od -An -N2 -i /dev/random`.tmp

Another/easiest way is to install rand using apt-get tool:

apt-get install rand

Now we can generate random number from this rand command:

rand
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