12-27-2017
Now, these are very basic questions from quite broad a range of IT, and I'm not sure I can cover that to satisfaction. On top, there may be a language barrier, e.g with "occurrence". I'd advise to use a dictionary, as - to me - the meaning got immediately clear when seeing the translations. Please also consult introductory text books and / or man pages.
It might be worthwhile to internalize the concept of a string which you will encounter everywhere in IT (tools, databases, documents, files, ...) when needing to represent text. It can come in a variety of shapes, like fixed or varying length strings, zero terminated or with a leading length indicator, string constants, substrings, string concatenations, and what have you, and there are many tools, libraries, functions to handle them. Different digital items (numbers, logical values) can be output to screen as readable text representations only, not as the individual items themselves.
Then, there are text files, a loosely structured collection of (mostly) printable characters. In *nix systems, those consist of lines of characters terminated by a <new line> (\n, ^J, 0x0A) character. But this is not the only possible text representation. When reading a line from a file, you can put it into a single string variable, or split it into several substrings. If you do so by applying spaces and / or punctuation chars for separating, the substrings will be words. But any other separation is possible albeit not necessarily sensible. So, a line is sort of a superset of (a group of) strings.
A "command line" specifies a collection of a command name (perhaps including a path), zero or more options (with possible arguments), and zero or more parameters. Any of those is a (possibly one character) string, analysed by the command interpreter, and then supplied to the program being executed. Please be aware that the terms "argument" and "parameter" are not strictly distinguished between and both are loosely and interchangably used. (I neglected possible local variable assingments and redirections to avoid overcomplicaton.)
Last edited by RudiC; 12-27-2017 at 10:13 AM..
Reason: Some typos
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Can I use xargs to send a list of commands to a process, to be acted upon individually? Here's what I have: a file that contains numbers, one per line. The desired outcome it to send each number to a DB2 query. I thought xargs would work, but it doesn't. I tried it like this:
cat file | xargs |... (4 Replies)
Discussion started by: jpprial
4 Replies
2. UNIX for Advanced & Expert Users
I discovered that GNU's xargs has a -P option to allow its processes to run in parallel. Great! Is this a GNU thing, or is it supported by other platforms as well? (4 Replies)
Discussion started by: otheus
4 Replies
3. Shell Programming and Scripting
hi
i just want to know that how do we use xargs command to find files which are greater than specified memory
in a given directory (6 Replies)
Discussion started by: sumit the cool
6 Replies
4. Shell Programming and Scripting
Hi,
I have a requirement to RCP the files from remote server to local server.
Also the RCP has to run in parallel. However using 'xargs' retrives 2 file names during each loop. How do we restrict to only one file name using xargs and loop till remaining files.
I use the below code for... (2 Replies)
Discussion started by: senthil3d
2 Replies
5. Shell Programming and Scripting
Hello there,
Let me show you a simple example of what I am trying to achieve:
1) I have an input text file with some lines:
1 a
2 b
3 c
2) And I want to run a command with these lines as arguments (+ arbitrary extra arguments). For example:
$ command "1 a" "2 b" "3 c" "bye"
I... (7 Replies)
Discussion started by: tokland
7 Replies
6. Shell Programming and Scripting
hi
Could any one please tell me the option using which we can run multiple commands using xargs
I have list of files, I want to run dos2unix and chmod at one shot on them
I tried google n searched man pages but couldnt really find the solution , please help
right now im doing this
ls... (4 Replies)
Discussion started by: sunilmenhdiratt
4 Replies
7. Shell Programming and Scripting
I have dir with many files ( close to 4M ) .
$ ls -la
total 76392
drwxr-xr-x 10 oracle dba 512 Jun 06 14:39 .
drwxr-xr-x 11 oracle dba 512 Dec 20 13:21 ..
drwxr-xr-x 2 oracle dba 39074816 Jun 15 14:07 ad
I am trying to delete them using... (8 Replies)
Discussion started by: talashil
8 Replies
8. Shell Programming and Scripting
Using the bash shell I'm trying to either create a command for the command line or a script that will show netstat info for a given process name. Here is an example of what I'm trying to do:$ ps aux |grep catalina |grep -v grep | awk '{print $2}'
5132
$ netstat -nlp |grep 5132
(Not all processes... (11 Replies)
Discussion started by: axiopisty
11 Replies
9. Shell Programming and Scripting
Hello, I need some help with xargs
$ ls
aaa bbb ccc ddd$ ls | xargs -I{} ls -la {}
-rw-rw-r--. 1 xxx xx 0 May 30 20:04 aaa
-rw-rw-r--. 1 xxx xx 0 May 30 20:04 bbb
-rw-rw-r--. 1 xxx xx 0 May 30 20:04 ccc
-rw-rw-r--. 1 xxx xx 0 May 30 20:04 dddit's possible to have output like this with... (3 Replies)
Discussion started by: vikus
3 Replies
10. UNIX for Dummies Questions & Answers
Hi,
can anyone tell me in detail ?
what the following do in detail ?
I am trying to get a largest number in a list
Thanks
Tao
LARGEST=$(echo $* | xargs -n1 | sort -nr | tail -1) (3 Replies)
Discussion started by: ccp
3 Replies
lorder(1) General Commands Manual lorder(1)
NAME
lorder - Finds the best order for member files in an object library
SYNOPSIS
lorder file...
DESCRIPTION
The lorder command is essentially obsolete. Use the following command in its place: % ar -ts file.a
The lorder command reads one or more object or library archive files, looks for external references, and writes a list of paired filenames
to standard output. The first of each pair of files contains references to identifiers that are defined in the second file. You can send
this list to the tsort command to find an ordering of a library member file suitable for 1-pass access by ld.
If object files do not end with lorder overlooks them and attributes their global symbols and references to some other file.
EXAMPLES
To create a subroutine library, enter: lorder charin.o scanfld.o scan.o scanln.o | tsort | xargs ar qv libsubs.a
(Enter this command entirely on one line, not on two lines as shown above.)
This creates a subroutine library named libsubs.a that contains charin.o, scanfld.o, scan.o, and scanln.o. The ordering of the object mod-
ules in the library is important. The lorder and tsort commands together add the subroutines to the library in the proper order.
Suppose that scan.o calls entry points in scanfld.o and scanln.o. scanfld.o also calls entry points in charin.o. First, the lorder command
creates a list of pairs that shows these dependencies: charin.o charin.o scanfld.o scanfld.o scan.o scan.o scanln.o scanln.o scanfld.o
charin.o scanln.o charin.o scan.o scanfld.o
This list is piped to the tsort command, which converts the list into the ordering that is needed:
scan.o scanfld.o scanln.o charin.o
Note that each module precedes the module it calls. charin.o, which does not call another module, is last. The second list is then piped
to xargs, which constructs and runs the following ar command: ar qv libsubs.a scan.o scanfld.o scanln.o charin.o
This ar command creates the properly ordered library.
FILES
Temporary files
SEE ALSO
Commands: ar(1), as(1), cc(1), ld(1), make(1), nm(1), size(1), strip(1), tsort(1), xargs(1)
Files: a.out(4), ar(4)
lorder(1)