Given the following table
$ connmanctl services
*AO MyNetwork wifi_dc85de828967_68756773616d_managed_psk
OtherNET wifi_dc85de828967_38303944616e69656c73_managed_psk
AnotherOne wifi_dc85de828967_3257495245363836_managed_wep
FourthNetwork wifi_dc85de828967_4d7572706879_managed_wep
AnOpenNetwork wifi_dc85de828967_4d6568657272696e_managed_none
I'd like to be able to connect to a network, e.g. OtherNET, using the string OtherNET rather than the long wifi_dc85de828967_38303944616e69656c73_managed_psk, as I don't want to count the times I press Tab and/or check that the wifi_ line in the prompt corresponds to the intended network.
Is this possible with connman only? Or do I really have to write a wrapper myself?
The man page of connmanctl contains
services
Shows a list of all available services. This includes the
nearby wifi networks, the wired ethernet connections, blue‐
tooth devices, etc. An asterisk in front of the service
indicates that the service has been connected before.
and
connect service
Connects to the given service. Some services need a so-
called provisioning file in order to connect to them, see
connman-service.config(5).
which both don't say much about the format of the output or the use of the command.
Similarly, the wiki on Arch Linux refers to the last column as the second field beginning with wifi_.
Since nobody has answered yet, I have found some spare time to code the following wrapper, which basically does the following
keeps reading as long as the input is not exit;
when an input is provided which starts with connect, the following word is used to pattern-match one line (only the first matching line) from connman services; the last field of this line (the one which starts with wifi_) is forwarded to connmanctl connect;
any other non-empty input is forwarded to connmanctl as it is.
a certain number (to be passed through the variable NOINPUTS_BEFORE_EXIT whose default is 3) of empty inputs causes the script to exit.
The script is the following
#!/usr/bin/env bash
name=$(basename $0)
noinputs_before_exit=${NOINPUTS_BEFORE_EXIT:=3}
while [[ $cmd != 'exit' ]]; do
echo -n "$name " 1>&2
read cmd
if [[ -z "$cmd" ]]; then
(( --noinputs_before_exit == 0 )) && exit
else
noinputs_before_exit=$NOINPUTS_BEFORE_EXIT
if [[ $cmd =~ ^connect\ ]]; then
connmanctl connect $(connmanctl services | awk '/'"${cmd#* }"'/ { print $NF; exit }')
else
connmanctl $cmd
fi
fi
done
The script limitations are at least the following:
(less importantly, to me) I have no idea whether it meets any security requirements;
it does not allow Tab-completion;
(most importantly, to me) it does not use the readline library, so line editing impossible.
when you scrutiny my questions from the past weeks you find I asked questions similar to this one. I had problems to ask in a demanded format since I did not really know where my problems came from. E. Morton tells me not to use range expression. Well, I do not know what they are excactly. I found in this forum many questions alike mine with working answers.
Like: "How to print following line from a match" (e.g.)
But all solutions I found stop working when I process more than one input file. I need to process many.
I use this command:
gawk -f 1.awk print*.csv > new.txt
while 1.awk contains:
BEGIN { OFS=FS=";"
pattern="row4"
}
go {print} $0 ~ pattern {go = 1}
input file 1 print1.csv contains:
row1;something;in;this;row;;;;;;;
row2;something;in;this;row;;;;;;;
row3;something;in;this;row;;;;;;;
row4;don't;need;to;match;the;whole;line,;
row5;something;in;this;row;;;;;;;
row6;something;in;this;row;;;;;;;
row7;something;in;this;row;;;;;;;
row8;something;in;this;row;;;;;;;
row9;something;in;this;row;;;;;;;
row10;something;in;this;row;;;;;;;
Input file 2 print2.csv contains the same just for illustration purpose.
The 1.awk (and several others ways I found in this forum to print from match) works for one file. Output:
row5;something;in;this;row;;;;;;;
row6;something;in;this;row;;;;;;;
row7;something;in;this;row;;;;;;;
row8;something;in;this;row;;;;;;;
row9;something;in;this;row;;;;;;;
row10;something;in;this;row;;;;;;;
BUT not when I process more input files.
Each time I process this way more than one input file awk commands 'to print from match' seem to be ignored.
As said I was told not to use range expression. I do not know how and maybe the problem is linked to the way I input several files?
just reset your match indicator at the beginning of each file
$ awk 'FNR==1{p=0} p; /row4/{p=1} ' file1 file2
row5;something;in;this;row;;;;;;;
row6;something;in;this;row;;;;;;;
row7;something;in;this;row;;;;;;;
row8;something;in;this;row;;;;;;;
row9;something;in;this;row;;;;;;;
row10;something;in;this;row;;;;;;;
row5;something;in;this;row;;;;;;;
row6;something;in;this;row;;;;;;;
row7;something;in;this;row;;;;;;;
row8;something;in;this;row;;;;;;;
row9;something;in;this;row;;;;;;;
row10;something;in;this;row;;;;;;;
UPDATE
From the comments
is it possible to combine your awk with: "If $1="row5" then write in
$6="row5" and delete the value "row5" in $5? In other words, to move
content "row5" in column1, if found there, to new column 6? I could to
this with another awk but a combination into one would be nicer
... $1=="row5"{$6=$5; $5=""} ...
or, if you want to use another field instead of $5 replace $5 with the corresponding field number.
I am using orgmode on Emacs and want to automatically update parts of an orgmode file using cron scheduling.
I know how to get the cron job to run at the times I choose but now I am faced with the issue of selecting certain parts of the file to change.
I would like to increment numbers at a certain locations in a file everyday (like every day at 3am or something).
So say I have the file fruit.org:
* Apple
age: 2
* Bananas
age: 1
A really bad fruit
* Cranberry
* Death
* Easter
A cool day
I want to select all the numerical values after age and then increment them every day. How would I do this selection and replacing. I believe it would involve regexp and some tool (maybe awk) but I am relatively clueless from there on.
In awk, you could say:
awk '/age:/ { $2++ } { print }' foo.org
If you have a recent version of GNU awk, you can edit the file in-place using the option -i inplace. Otherwise, just do the usual, i.e. redirect to a temporary file and then replace the original:
awk '/age:/ { $2++ } { print }' foo.org > foo.org.tmp && mv foo.org{.tmp,}
That's basically what the inplace option of awk or sed does behind the scenes anyway.
I have a problem with ksh in that a while loop is failing to obey the "while" condition. I should add now that this is ksh88 on my client's Solaris box. (That's a separate problem that can't be addressed in this forum. ;) I have seen Lance's question and some similar but none that I have found seem to address this. (Disclaimer: NO I haven't looked at every ksh question in this forum)
Here's a very cut down piece of code that replicates the problem:
1 #!/usr/bin/ksh
2 #
3 go=1
4 set -x
5 tail -0f loop-test.txt | while [[ $go -eq 1 ]]
6 do
7 read lbuff
8 set $lbuff
9 nwords=$#
10 printf "Line has %d words <%s>\n" $nwords "${lbuff}"
11 if [[ "${lbuff}" = "0" ]]
12 then
13 printf "Line consists of %s; time to absquatulate\n" $lbuff
14 go=0 # Violate the WHILE condition to get out of loop
15 fi
16 done
17 printf "\nLooks like I've fallen out of the loop\n"
18 exit 0
The way I test this is:
Run loop-test.sh in background mode
In a different window I run commands like "echo some nonsense >>loop_test.txt" (w/o the quotes, of course)
When I wish to exit, I type "echo 0 >>loop-test.txt"
What happens? It indeed sets go=0 and displays the line:
Line consists of 0; time to absquatulate
but does not exit the loop. To break out I append one more line to the txt file. The loop does NOT process that line and just falls out of the loop, issuing that "fallen out" message before exiting.
What's going on with this? I don't want to use "break" because in the actual script, the loop is monitoring the log of a database engine and the flag is set when it sees messages that the engine is shutting down. The actual script must still process those final lines before exiting.
Open to ideas, anyone?
Thanks much!
-- J.
OK, that flopped pretty quick. After reading a few other posts, I found an answer given by dogbane that sidesteps my entire pipe-to-while scheme. His is the second answer to a question (from 2013) where I see neeraj is using the same scheme I'm using.
What was wrong? The pipe-to-while has always worked for input that will end, like a file or a command with a distinct end to its output. However, from a tail command, there is no distinct EOF. Hence, the while-in-a-subshell doesn't know when to terminate.
Dogbane's solution: Don't use a pipe. Applying his logic to my situation, the basic loop is:
while read line
do
# put loop body here
done < <(tail -0f ${logfile})
No subshell, no problem.
Caveat about that syntax: There must be a space between the two < operators; otherwise it looks like a HEREIS document with bad syntax.
Er, one more catch: The syntax did not work in ksh, not even in the mksh (under cygwin) which emulates ksh93. But it did work in bash. So my boss is gonna have a good laugh at me, 'cause he knows I dislike bash.
So thanks MUCH, dogbane.
-- J
After articulating the problem and sleeping on it, the reason for the described behavior came to me: After setting go=0, the control flow of the loop still depends on another line of data coming in from STDIN via that pipe.
And now that I have realized the cause of the weirdness, I can speculate on an alternative way of reading from the stream. For the moment I am thinking of the following solution:
Open the input file as STDIN (Need to research the exec syntax for that)
When the condition occurs, close STDIN (Again, need to research the syntax for that)
It should then be safe to use the more intuitive:while read lbuffat the top of the loop.
I'll test this out today and post the result. I'd hope someone else benefit from the method (if it works).
It's the first great virtue of programmers. All of us have, at one time or another automated a task with a bit of throw-away code. Sometimes it takes a couple seconds tapping out a one-liner, sometimes we spend an exorbitant amount of time automating away a two-second task and then never use it again.
What tiny hack have you found useful enough to reuse? To make go so far as to make an alias for?
Note: before answering, please check to make sure it's not already on favourite command-line tricks using BASH or perl/ruby one-liner questions.
i found this on dotfiles.org just today. it's very simple, but clever. i felt stupid for not having thought of it myself.
###
### Handy Extract Program
###
extract () {
if [ -f $1 ] ; then
case $1 in
*.tar.bz2) tar xvjf $1 ;;
*.tar.gz) tar xvzf $1 ;;
*.bz2) bunzip2 $1 ;;
*.rar) unrar x $1 ;;
*.gz) gunzip $1 ;;
*.tar) tar xvf $1 ;;
*.tbz2) tar xvjf $1 ;;
*.tgz) tar xvzf $1 ;;
*.zip) unzip $1 ;;
*.Z) uncompress $1 ;;
*.7z) 7z x $1 ;;
*) echo "'$1' cannot be extracted via >extract<" ;;
esac
else
echo "'$1' is not a valid file"
fi
}
Here's a filter that puts commas in the middle of any large numbers in standard input.
$ cat ~/bin/comma
#!/usr/bin/perl -p
s/(\d{4,})/commify($1)/ge;
sub commify {
local $_ = shift;
1 while s/^([ -+]?\d+)(\d{3})/$1,$2/;
return $_;
}
I usually wind up using it for long output lists of big numbers, and I tire of counting decimal places. Now instead of seeing
-rw-r--r-- 1 alester alester 2244487404 Oct 6 15:38 listdetail.sql
I can run that as ls -l | comma and see
-rw-r--r-- 1 alester alester 2,244,487,404 Oct 6 15:38 listdetail.sql
This script saved my career!
Quite a few years ago, i was working remotely on a client database. I updated a shipment to change its status. But I forgot the where clause.
I'll never forget the feeling in the pit of my stomach when I saw (6834 rows affected). I basically spent the entire night going through event logs and figuring out the proper status on all those shipments. Crap!
So I wrote a script (originally in awk) that would start a transaction for any updates, and check the rows affected before committing. This prevented any surprises.
So now I never do updates from command line without going through a script like this. Here it is (now in Python):
import sys
import subprocess as sp
pgm = "isql"
if len(sys.argv) == 1:
print "Usage: \nsql sql-string [rows-affected]"
sys.exit()
sql_str = sys.argv[1].upper()
max_rows_affected = 3
if len(sys.argv) > 2:
max_rows_affected = int(sys.argv[2])
if sql_str.startswith("UPDATE"):
sql_str = "BEGIN TRANSACTION\\n" + sql_str
p1 = sp.Popen([pgm, sql_str],stdout=sp.PIPE,
shell=True)
(stdout, stderr) = p1.communicate()
print stdout
# example -> (33 rows affected)
affected = stdout.splitlines()[-1]
affected = affected.split()[0].lstrip('(')
num_affected = int(affected)
if num_affected > max_rows_affected:
print "WARNING! ", num_affected,"rows were affected, rolling back..."
sql_str = "ROLLBACK TRANSACTION"
ret_code = sp.call([pgm, sql_str], shell=True)
else:
sql_str = "COMMIT TRANSACTION"
ret_code = sp.call([pgm, sql_str], shell=True)
else:
ret_code = sp.call([pgm, sql_str], shell=True)
I use this script under assorted linuxes to check whether a directory copy between machines (or to CD/DVD) worked or whether copying (e.g. ext3 utf8 filenames -> fusebl
k) has mangled special characters in the filenames.
#!/bin/bash
## dsum Do checksums recursively over a directory.
## Typical usage: dsum <directory> > outfile
export LC_ALL=C # Optional - use sort order across different locales
if [ $# != 1 ]; then echo "Usage: ${0/*\//} <directory>" 1>&2; exit; fi
cd $1 1>&2 || exit
#findargs=-follow # Uncomment to follow symbolic links
find . $findargs -type f | sort | xargs -d'\n' cksum
Sorry, don't have the exact code handy, but I coded a regular expression for searching source code in VS.Net that allowed me to search anything not in comments. It came in very useful in a particular project I was working on, where people insisted that commenting out code was good practice, in case you wanted to go back and see what the code used to do.
I have two ruby scripts that I modify regularly to download all of various webcomics. Extremely handy! Note: They require wget, so probably linux. Note2: read these before you try them, they need a little bit of modification for each site.
Date based downloader:
#!/usr/bin/ruby -w
Day = 60 * 60 * 24
Fromat = "hjlsdahjsd/comics/st%Y%m%d.gif"
t = Time.local(2005, 2, 5)
MWF = [1,3,5]
until t == Time.local(2007, 7, 9)
if MWF.include? t.wday
`wget #{t.strftime(Fromat)}`
sleep 3
end
t += Day
end
Or you can use the number based one:
#!/usr/bin/ruby -w
Fromat = "http://fdsafdsa/comics/%08d.gif"
1.upto(986) do |i|
`wget #{sprintf(Fromat, i)}`
sleep 1
end
Instead of having to repeatedly open files in SQL Query Analyser and run them, I found the syntax needed to make a batch file, and could then run 100 at once. Oh the sweet sweet joy! I've used this ever since.
isqlw -S servername -d dbname -E -i F:\blah\whatever.sql -o F:\results.txt
This goes back to my COBOL days but I had two generic COBOL programs, one batch and one online (mainframe folks will know what these are). They were shells of a program that could take any set of parameters and/or files and be run, batch or executed in an IMS test region. I had them set up so that depending on the parameters I could access files, databases(DB2 or IMS DB) and or just manipulate working storage or whatever.
It was great because I could test that date function without guessing or test why there was truncation or why there was a database ABEND. The programs grew in size as time went on to include all sorts of tests and become a staple of the development group. Everyone knew where the code resided and included them in their unit testing as well. Those programs got so large (most of the code were commented out tests) and it was all contributed by people through the years. They saved so much time and settled so many disagreements!
I coded a Perl script to map dependencies, without going into an endless loop, For a legacy C program I inherited .... that also had a diamond dependency problem.
I wrote small program that e-mailed me when I received e-mails from friends, on an rarely used e-mail account.
I wrote another small program that sent me text messages if my home IP changes.
To name a few.
Years ago I built a suite of applications on a custom web application platform in PERL.
One cool feature was to convert SQL query strings into human readable sentences that described what the results were.
The code was relatively short but the end effect was nice.
I've got a little app that you run and it dumps a GUID into the clipboard. You can run it /noui or not. With UI, its a single button that drops a new GUID every time you click it. Without it drops a new one and then exits.
I mostly use it from within VS. I have it as an external app and mapped to a shortcut. I'm writing an app that relies heavily on xaml and guids, so I always find I need to paste a new guid into xaml...
Any time I write a clever list comprehension or use of map/reduce in python. There was one like this:
if reduce(lambda x, c: locks[x] and c, locknames, True):
print "Sub-threads terminated!"
The reason I remember that is that I came up with it myself, then saw the exact same code on somebody else's website. Now-adays it'd probably be done like:
if all(map(lambda z: locks[z], locknames)):
print "ya trik"
I've got 20 or 30 of these things lying around because once I coded up the framework for my standard console app in windows I can pretty much drop in any logic I want, so I got a lot of these little things that solve specific problems.
I guess the ones I'm using a lot right now is a console app that takes stdin and colorizes the output based on xml profiles that match regular expressions to colors. I use it for watching my log files from builds. The other one is a command line launcher so I don't pollute my PATH env var and it would exceed the limit on some systems anyway, namely win2k.
I'm constantly connecting to various linux servers from my own desktop throughout my workday, so I created a few aliases that will launch an xterm on those machines and set the title, background color, and other tweaks:
alias x="xterm" # local
alias xd="ssh -Xf me#development_host xterm -bg aliceblue -ls -sb -bc -geometry 100x30 -title Development"
alias xp="ssh -Xf me#production_host xterm -bg thistle1 ..."
I have a bunch of servers I frequently connect to, as well, but they're all on my local network. This Ruby script prints out the command to create aliases for any machine with ssh open:
#!/usr/bin/env ruby
require 'rubygems'
require 'dnssd'
handle = DNSSD.browse('_ssh._tcp') do |reply|
print "alias #{reply.name}='ssh #{reply.name}.#{reply.domain}';"
end
sleep 1
handle.stop
Use it like this in your .bash_profile:
eval `ruby ~/.alias_shares`