file allids consists of 300,000 rows, each containing a 5-7 digit numeric id. file newids consists of 20,000 rows of id's. How do you explain the following timings? time: 0.07s:
Code:
diff <(sort allids) <(sort newids)
time: 1.6s:
[code].....
Further to solved LQ thread Bash: how to populate a list of arbitrarily named files?, what is the functional difference between feeding a loop with process substitution and feeding it with a here string with embedded command substitution? ABSG pages: process substitution, here string and command substitution. This works
Code:
while IFS= read -r -d '' file
do
files+=("$file")
done < <(find $dir -type f -print0)
[code]....
Just a simple BASH for loop to read the file path from a text file (clean.txt) echo the variable for debug purposes, and scp it to a server I have using port 50 for SSH.
I've already formatted the entries in clean.txt to handle spaces correctly, using sed replacement.
Example from the clean.txt file:
Code:
/MP3/NAS000000001/Barenaked Ladies/Barenaked Ladies - Barenaked For The Holidays/20 Auld Lang Syne.mp3
/MP3/NAS000000001/Barenaked Ladies/Barenaked Ladies - Barenaked For The Holidays/14 Deck the Stills.mp3
[Code]....
I'm trying to use ${VAR:0:4} substring extraction described here: tldp.org/LDP/abs/html/string-manipulation.html and it works perfectly if i issue a command in bash. But when i put it in a script file and run it, bash gives me "bad substitution" error. Does anyone know how to fix it?
View 5 Replies View RelatedI'm trying to get the substring of a string in bash. Here is the code:
Code:
#! /bin/bash
LOCAL_HOSTNAME=$(hostname)
echo $LOCAL_HOSTNAME
INDEX_OF=`expr index "$LOCAL_HOSTNAME" 1`
echo $INDEX_OF
SERVER_HOSTNAME=${LOCAL_HOSTNAME:0:INDEX_OF}
echo $SERVER_HOSTNAME
It's supposed to get the current hostname, assign it to variable LOCAL_HOSTNAME, get the first occurrence of "1" from hostname and assign value to INDEX_OF, the get the substring from variable LOCAL_HOSTNAME (starting at index 0 through INDEX_OF) and asign it to SERVER_HOSTNAME. No matter how much I've tried it keeps throwing Bad substitution error at the substring. I've searched and it says it has to be bash... but it is bash, both the sh script and the running shell. The LOCAL_HOSTNAME and INDEX_OF variables are ok.
Here is the output:
I've also tried to get the substring without the INDEX_OF but it gives the same error: SERVER_HOSTNAME=${LOCAL_HOSTNAME:0}
Code:
host1
5
test.sh: 7: Bad substitution
if i run /bin/dash at the command prompt I get the message /bin/dash: Bad substitution shown repeatedly until I kill the process
View 14 Replies View RelatedThe first call to "somefunction" works as expected. The function prints "endfunction" and a process in background sleeps 30 seconds. In the second call I thought it should work in the same way, but the script sleeps 30 seconds before it prints "endfunction".Does someone know the reason of this behavior? Is there another way to do a command substitution of a function that has a background process without have to waiting for that process?
View 2 Replies View RelatedI'm writing a C++ application and need to work with process substitution in the Bash shell. I'm trying to find a way to validate the paths passed as arguments to my program, some of which point to FIFO files created by process substitution.
Is there a shell (or C++) way that I can check if the system creates these files in /dev/fd or if they are created somewhere else?
I was to set up a cronjob that sends its output to a logfile, i want that log file to be unique. the easiest way to set this up would be to make the directory in the script, then output the command to that directory, they call that directory via is full path in cron (because cron only uses full path names.
This does not work
keep in mind the command "/bin/mkdir -p /tmp/pw_log/`date +20%y%m%d_%H%M%S`.log" works fine on the command line - but once I put it in the shell, it does not work.
pretty simple. how would you background a process from a script and get its process id at the same time?
View 6 Replies View RelatedI am new to scripting and been working on this bash script for awhile now. I been researching this problem, but I can't seem to find a solution. I was wondering if someone could please help me out. Here is my script:
#!/bin/bash
NO="ps -ef | grep NO | grep -v grep"
NOWC=`ps -ef | grep NO | grep -v grep | wc -l`
[code].....
I cannot get this script to run the "ps -ef" command on the client. It get its value from the host machine that I am running this script from. I need this command to execute on the client. When I run the command (ps -ef | grep NO | grep -v grep) on the client, I get something back. Here is what I get when I try to debug the script.
XX# ./test_ps5.sh XXXXX
+ NO='ps -ef | grep NO | grep -v grep'
++ ps -ef
[code]....
I have the following test code fragment:
Code:
When I try to run it 'sh' reports the following message^
Code:
You might understand what I mean with that test code so could you recommend how to achieve the required effect?
I'm working on a program that will allow non-privileged users the ability to substitute passwords that are read in from a 600-root:root file.
A user might call it like this:
/bin/securepasswrapper "/path/to/check_ping -u Admin -p ?webserver1?"
The file (defined now as /tmp/securefile) will be searched for the identifier "webserver1", and it's corresponding password will be returned to securepasswrapper. Now, I know you could just call /bin/echo, and get the output, but that's in scope at this point.
File format of securefile is:
<identifierassword>
ex: webserver1:asdf123
Once the password is properly substituted in, securepasswrapper should then execute it as the UID/EUID of the calling user (not root)...that part I've not got to yet.
Code:
/* program: securepasswrapper
author: R.Briggs + Google
date: 02/02/11
purpose: C wrapper that replaces placeholders in a string with secure passwords retrieved from a file
*/ .....
I have an interpteter that supports string literals, and the way it works is that the lexer returns the entire string as a single token, with the quotes removed and escape sequences replaced with the literal characters they represent.
I already implemented single-quote strings, they don't interpret any characters specially except for the single quote. I partially implemented double-quoted strings, they already support all the same backslash escape sequences that C does. But I would also want to add variable substitution.
The way it would work is that "${expression}" would interpret the expression (which could just be a variable name) and replace itself with the result. But I have no idea how to do this.
In case it matters, I'm using a hand-written lexer and recursive-descent parser.
I made a little rsync script for log transfer.
Code:
SERVERS=(SERVER1 SERVER2 SERVER3)
SERVER1_SERV=(web ftp mail)
SERVER2_SERV=(web transcoding)
SERVER3_SERV=(web ftp mail)
for SERVER in ${SERVERS[@]}
do
echo "Starting tranfer for server $SERVER"
for SERVICE in ${$SERVER_$SERVICE[@]}
do
something_to_be_done
fi
done
But when I run it I get ${$SERVER_$SERVICE[@]}: bad substitution
I have a simple script that I am writing to parse an XML file for me, and update some version numbers. Basically what happens in my script is that I'm running a grep command on the file to get the current version number, then I prompt for a new number, and then I want to globally replace that version number in the file. The problem is, the sed command seems to only want literal values (it doesn't appear to be capable of resolving variables). For example, this code doesn't work:
[Code]...
I have tried removing the curly brackets from the variable names, quoting them, etc. and nothing seems to work. Should I do this with awk instead (and if so can you kindly write out the command for me because I never bothered to learn awk).
I remember reading that using sed, you can do this with parentheses: s/abc(something)def/(something)else/g I can't find an explanation of how to do something like this with Awk. Say you have this in an HTML file, where (number) stands for a one or two-digit number:
<sup>(number)</sup>
And you want to change that to this:
<a name="(number)t" href="#(number)b"><sup>(number)</sup></a>
How would this be possible? Would you have to use sed?
I need a substitution of a particular string (StringA) with another string (StringB). However, there may be more than one occurrence of StringA within the file, but only one instance needs to be changed, which is why I'm trying to be sure of it's positioning against something I know will be unique in the file, and will always have the same distance from the string to be replaced. So, I intend to match on a string (StringC) above the string to be substituted and then have sed go to StringA below and replace with StringB.
So far, I have had some success with the following:
Code:
... but I can't help thinking that there *has* to be a cleaner way of doing it.
I have the following TCL code:
if{ [catch {sqlite3 db /path/to/db/file} result] } {
puts stderr $result
} else {
do something
}
What I want is to use a variable for the file name/path. When I put in a variable instead of the absolute path, I get an error: "missing close-brace: possible unbalanced brace in comment while executing"
This is weird because when I run the code with the fully qualified pathname, it works fine. I substitute out the pathname for a variable containing the pathname ($variable) and I get this error.
I can find points to Tillies Garrels TLDP reference. Do I want to create my own variable to hold the string or do I want to place the string in memory? Is that my problem? Or is something different causing the 'bad substitution' error.
[code]...
I know this may be just me being a little bias on OS's but... I quite honestly believe that "some" programs run faster on linux than on windows.
Open Office for example, It runs amazingly fast on my linux distro but runs horribly (laggy) on my Vista machine.
Firefox also appears to run faster on my linux machine than on my Vista machine.
There are several more examples but I could go on and on with this.
My point is, do programs run faster on linux than on windows? Or is it just me that is in denial?
I am not sure if comparing linux to Vista is a good comparison in terms of program speed or not...
Also it should be noted that the Vista machine "hardware" is "several" times faster than my linux machine's "hardware".
I am not trying to start a flame war or anything like that, I am just trying to make sure I haven't totally lost my mind.
Which is faster:
fread(&buf, 1, 1024, fp);
or
fread(&buf, 1024, 1, fp);
[code]...
I'm writing an interpreter and it used simple association lists for mapping varaible names to their values. Here's the code:
Code:
#include "assoc_array.hpp"
#include <string.h>
using namespace LANG_NAMESPACE;
[code]....
I thought that I would replace it with a hash table to increase performance. Note that I decided to store linked lists in the buckets instead of the actual values, in case the hash function outputs the same index for multiple variable names:
Code:
#include "hash_table.hpp"
#include "assoc_array.hpp"
#include <string.h>
[code]....
It runs in about 0.333 seconds on my machine. Since I'm using git version control, I decided to bring back the old version that used association lists. To my amazement, it ran 3 times faster, completing in 0.116 seconds! Is my hash table implementaion really that bad, or is this a really poor benchmark (and real-world code actually will be faster using the hash table)?
I have a shell script to identify whether the process is running or not. If the process is not running, then I execute another script file to run my application. Below is my script and saved this script as monitorprocess.sh Code: #!/bin/bash
result=$(ps -ef | grep -v grep | grep "applicationname.sh" | awk '{print $2}')
echo $result
if [ "$result" == "" ];
[code]...
Is there any difference in cpu usage for process in init.rc(runs automatic when boot is happened) and manually running process. Will these both have same priority by default...?
View 1 Replies View RelatedI tried googling but didn't get any answer for this.I have a process called "abc" and it is running with PID "123".I have a putty session opened with PID "999".I am giving kill -TERM 123 from putty session.My process "abc" before dying it should catch the PID of the terminal which provided TERM signal to it.Is there any way to find this out
View 2 Replies View RelatedI am having a problem identifying a BASH script process that I run at startup.When I use "ps -e", I see a few BASH and SH processes running, but I don't know if any of these are my script. Is there a way to give a BASH script a specific name when run that I could see as the process name. That would make it easier to identify and kill when needed.
View 3 Replies View RelatedI would like to know how do I print the line # in a script. My requirement is, I have a script which is about ~5000 lines long. If there are any errors happen I just exit. And I would like to add the line # of the script where the error happened.
View 3 Replies View Relatedsimple bash code:
Code:
#!/bin/bash
trap "echo 'you got me'" SIGINT SIGTERM # to trap ctrl+c
echo "Press ctrl+c during 5 sec loop"
for ((i=0;i<5;i++)); do
[Code]...
How come code behaves normally and stops when ctrl+c signal is caught and resumes, but after I use at least one timeout read in the code it looks like, if signal is caught again it doesn't pause the execution but skips the loop. If you remove -t (timeout) option from the read, both loops look the same!
I have a shell script to identify whether the process is running or not. If the process is not running, then I execute another script file to run my application. Below is my script and saved this script as monitorprocess.sh
Code:
#!/bin/bash
result=$(ps -ef | grep -v grep | grep "applicationname.sh" | awk '{print $2}')
[code]...
