I'm trying to understand xargs, though. What does that do for me here? I only ask b/c I've never used before.
It is possible to have written the command like this:
except that the result of the egrep might be more arguments than can be handled on a single command line. By piping the output to xargs, xargs will execute the command that you give it (cat in this case) with n number of arguments such that n does not exceed the limit from a command line perspective. It may invoke the command multiple times to accomplish its task.
With this said, I realise that my original command would be flawed as the '*' given to egrep might expand into too many arguments, causing an error, and thus the xargs in this case would do no good. This would probably be better:
The ls command generates a list of filenames which is given to egrep via the first xargs. The result of the searches is then given to cat via the second xargs.
When writing a script it is usually best to assume the worst case and use xargs in this situation. If you're willing to live with the errors, and are pretty sure that there will not be more files in a directory than the max allowable args on a command line, then the first form (without xargs) is easiest and straightforward.
Hi,
I need to get the latest file from a list of files in a particular directory.
Please could anyone help me out to get the file.
Thank you,
- Jay. (1 Reply)
I would like ot create shell script/ bash to create diffrent files based on a file and parameters list.
Here is the detail example: I have a textfile and four static parameter files (having ‘?'). mainfile.txt has below records (this count may be more than 50)
A200001
A200101
B200001... (9 Replies)
Good morning guys!!
Im still practicing with Perl and now Im trying to open a file, and copy its contents to another file. Them I want to remeove the information out of the orginal file after it is copied over.
The flow should be messages-->messages1-->messages2.
Kind of like a log... (1 Reply)
Hello,
I'm trying to move the log files from the parent directory to respective monthly folder and I would be running this script on a weekly basis through cron.
I'm new to this scripting and here is what i could come up and it runs without really doing anything. I even tried placing echo... (2 Replies)
hi
i want to scp files from remote server B to my local server A...
and i have a file containing list of all files to be scped from remote server B
there is a passwordless connectivity set between remote server and my local server.
need a ksh script.. with a for loop that goes through... (2 Replies)
Hi,
I'm quite new to ksh scripting, can someone help me with this.
Requirements:
I need to create a script that list the files from a user input date range.
e. g. format of file:
*c1*log.2012-12-22-14-00*
*c1*log.2012-12-22-14-00*
*c1*log.2012-12-22-14-00*... (7 Replies)
Hi,
I need help with this-
input.txt :
L B white
X Y white
A B brown
M Y black
Read this input file and if 3rd column is "white", then add specific lines to another file insert.txt.
If 3rd column is brown, add different set of lines to insert.txt, and so on.
For example, the given... (6 Replies)
Hi,
I have two pipe separated files as below:
head -3 file1.txt
"HD"|"Nov 11 2016 4:08AM"|"0000000018"
"DT"|"240350264"|"56432"
"DT"|"240350264"|"56432"
head -3 file2.txt
"HD"|"Nov 15 2016 2:18AM"|"0000000019"
"DT"|"240350264"|"56432"
"DT"|"240350264"|"56432"
I want to list the... (6 Replies)
Hi All,
In the file names we have dates.
Based on the file format given by the user,
if any file is not existed for a particular date with in a given interval we should consider that file is missing.
I have the below files in the directory /bin/daily/voda_files.
... (9 Replies)
Discussion started by: nalu
9 Replies
LEARN ABOUT BSD
xargs
XARGS(1) General Commands Manual XARGS(1)NAME
xargs - construct argument list(s) and execute utility
SYNOPSIS
xargs [ -t ][[ -x ] -n number ][ -s size ][ utility [ arguments... ]]
DESCRIPTION
The xargs utility reads space, tab, newline and end-of-file delimited arguments from the standard input and executes the specified utility
with them as arguments.
The utility and any arguments specified on the command line are given to the utility upon each invocation, followed by some number of the
arguments read from standard input. The utility is repeatedly executed until standard input is exhausted.
Spaces, tabs and newlines may be embedded in arguments using single (`` ' '') or double (``"'') quotes or backslashes (``''). Single
quotes escape all non-single quote characters, excluding newlines, up to the matching single quote. Double quotes escape all non-double
quote characters, excluding newlines, up to the matching double quote. Any single character, including newlines, may be escaped by a back-
slash.
The options are as follows:
-n number Set the maximum number of arguments taken from standard input for each invocation of the utility. An invocation of utility will
use less than number standard input arguments if the number of bytes accumulated (see the s option) exceeds the specified size or
there are fewer than number arguments remaining for the last invocation of utility. The current default value for number is
5000.
-s size Set the maximum number of bytes for the command line length provided to utility. The sum of the length of the utility name and
the arguments passed to utility (including /dev/null terminators) will be less than or equal to this number. The current default
value for size is ARG_MAX - 2048.
-t Echo the command to be executed to standard error immediately before it is executed.
-x Force xargs to terminate immediately if a command line containing number arguments will not fit in the specified (or default)
command line length.
If no utility is specified, echo(1) is used.
Undefined behavior may occur if utility reads from the standard input.
The xargs utility exits immediately (without processing any further input) if a command line cannot be assembled, utility cannot be
invoked, an invocation of the utility is terminated by a signal or an invocation of the utility exits with a value of 255.
The xargs utility exits with a value of 0 if no error occurs. If utility cannot be invoked, xargs exits with a value of 127. If any other
error occurs, xargs exits with a value of 1.
SEE ALSO echo(1), find(1)STANDARDS
The xargs utility is expected to be IEEE Std 1003.2("POSIX") compliant.
June 6, 1993 XARGS(1)