Adding one more small example here too. In awk, strings could be converted to numbers and numbers could be converted to strings, if the context of the awk program demands it. For example, If numeric values appear in string concatenation, they are converted to strings. Consider the following:
This prints the (numeric) value 27. The numeric values of the variables two and three are converted to strings and concatenated together. The resulting string is converted back to the number 23, to which 4 is then added. Also while taking 5th field of dfin BASH means to have the used file system percentage could be one more example for this too.
Thanks,
R. Singh
Last edited by RavinderSingh13; 05-26-2016 at 05:04 PM..
Hi,
I am facing one problem only with mv command not with cp command. I have a test program
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <fcntl.h>
#include <errno.h>
int sync_file(char *file)
{
FILE *fp=NULL;... (6 Replies)
Hello all,
Here is what my bash script does: sums number columns, saves the tot in new column, outputs if tot >= threshold val:
> cat getnon0file.sh
#!/bin/bash
this="getnon0file.sh"
USAGE=$this"
InFile="xyz.38"
Min="0.05"
#
awk '{sum=0; for(n=2; n<=NF; n++){sum+=$n};... (4 Replies)
What is the difference between (unix-system “which ) and which commands.
For example when I use the (unix-system “which visual_elite) command I get the following result:
/home/vhdl/edatools/mentor/visualelite/VisualElite-4.2.1/Linux2.4/bin/visual_elite
When I do the same on... (1 Reply)
Hey there,
I just stumbled upon a difference between using awk on the commandline and using it in a shellscript.
I have a variable, e.g.: PROG=vim
then i want to check if the package with this name is installed: TEMPVAL=$(dpkg -l | awk '{ if ($2 == "$PROG") print $2 }') (Im using... (10 Replies)
Hello,
I have two text files, each with a single column,
file 1:
124152970
123899868
123476854
54258288
123117283
file 2:
124152970
123899868
54258288
123117283
122108330 (5 Replies)
I have awk appearing to behave inconsistently. With the same variable it will give the message:
fatal: attempt to use array `X' in a scalar context
and, if I try to correct that, then:
fatal: attempt to use a scalar value as array
I'm using a three dimensional array. There seems to be a... (2 Replies)
so, im going over one of my scripts and trying to optimize it.
i have a code like this:
cksum sjreas.py | awk '{prinnt $1$2}'
This does what I need. However, i dont want to call the external command awk. so im doing this:
cksum sjreas.py | while OFS=' ' read v1 v2 ; do printf... (4 Replies)
In the awk I am trying to subtract the difference $3-$2 of each matching $4 before the first _ (underscore) and print that value in $13.
I think the awk will do that, but added comments. What I am not sure off is how to add a line or lines that will add sum each matching $13 value and put it in... (2 Replies)
Discussion started by: cmccabe
2 Replies
LEARN ABOUT FREEBSD
sleep
SLEEP(1) BSD General Commands Manual SLEEP(1)NAME
sleep -- suspend execution for an interval of time
SYNOPSIS
sleep seconds
DESCRIPTION
The sleep command suspends execution for a minimum of seconds.
If the sleep command receives a signal, it takes the standard action. When the SIGINFO signal is received, the estimate of the amount of
seconds left to sleep is printed on the standard output.
IMPLEMENTATION NOTES
The SIGALRM signal is not handled specially by this implementation.
The sleep command allows and honors a non-integer number of seconds to sleep in any form acceptable by strtod(3). This is a non-portable
extension, and its use will nearly guarantee that a shell script will not execute properly on another system.
EXIT STATUS
The sleep utility exits 0 on success, and >0 if an error occurs.
EXAMPLES
To schedule the execution of a command for x number seconds later (with csh(1)):
(sleep 1800; sh command_file >& errors)&
This incantation would wait a half hour before running the script command_file. (See the at(1) utility.)
To reiteratively run a command (with the csh(1)):
while (1)
if (! -r zzz.rawdata) then
sleep 300
else
foreach i (`ls *.rawdata`)
sleep 70
awk -f collapse_data $i >> results
end
break
endif
end
The scenario for a script such as this might be: a program currently running is taking longer than expected to process a series of files, and
it would be nice to have another program start processing the files created by the first program as soon as it is finished (when zzz.rawdata
is created). The script checks every five minutes for the file zzz.rawdata, when the file is found, then another portion processing is done
courteously by sleeping for 70 seconds in between each awk job.
SEE ALSO nanosleep(2), sleep(3)STANDARDS
The sleep command is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.
HISTORY
A sleep command appeared in Version 4 AT&T UNIX.
BSD April 18, 1994 BSD