The tag has no wiki summary.

learn more… | top users | synonyms

13
votes
7answers
862 views

What is the difference between $* and $@?

Consider the following code: foo () { echo $* } bar () { echo $@ } foo 1 2 3 4 bar 1 2 3 4 It outputs: 1 2 3 4 1 2 3 4 I am using Ksh88, but I am interested in other common ...
4
votes
2answers
2k views

CP: max source files number arguments for copy utility

Consider that there are countless number of files under /src/ cp /src/* /dst/ How many files cp will successfully process?
1
vote
5answers
7k views

Pass the output of previous command to next as an argument

I've a command that outputs data to stdout (command1 -p=aaa -v=bbb -i=4). The output line can have the following value: rate (10%) - name: value - 10Kbps I want to grep that output in order to ...
9
votes
2answers
2k views

How does ps know to hide passwords?

Witness: $ ps f PID TTY STAT TIME COMMAND 31509 pts/3 Ss 0:01 -bash 27266 pts/3 S+ 0:00 \_ mysql -uroot -p 25210 pts/10 Ss+ 0:00 /bin/bash 24444 pts/4 Ss 0:00 ...
10
votes
3answers
905 views

What defines the maximum size for a command single argument?

I was under the impression that the maximum length of a single argument was not the problem here so much as the total size of the overall argument array plus the size of the environment, which is ...
4
votes
2answers
5k views

Solving “mv: Argument list too long”?

I have a folder with more than a million files that needs sorting, but I cant really do anything because mv outputs this message all the time -bash: /bin/mv: Argument list too long I'm using this ...
4
votes
3answers
2k views

Bash script that reads filenames from a pipe or from command line args?

I want my script to read a bunch of filenames (which may have spaces) given either as a glob or from STDIN and do stuff with them. I've been able to read either way separately, but not combine them. ...
15
votes
2answers
554 views

How can I stream data to a program that expects to read data from a file that is given as a argument?

I have a huge gzipped file and I want a program (4s-import in this case) to read it. It takes a lot of time to first unzip the file and then call the program with the path to the file as an argument. ...
34
votes
7answers
3k views

Is `-` used only with cd?

cd - can switch between current dir and previous dir. It seems that I have seen - used as arguments to other commands before, though I don't remember if - means the same as with cd. I found that - ...
8
votes
3answers
1k views

Why do some commands not read from their standard input?

I wonder what when we should use pipeline and when we shouldn't. Say for instance, to kill certain process which handling pdf files, the following will not work by using pipeline: ps aux | grep pdf ...
4
votes
2answers
2k views

Is there an easy way to log all commands executed, including command line arguments?

I am trying to find how to log a specific instantiation of rrdtool to see whether the path it is receiving is incorrect. I know I could wrap the executable in a shell script that would log the ...
7
votes
2answers
701 views

What is a canonical way to find the actual maximum argument list length?

Following ARG_MAX, maximum length of arguments for a new process it seems like ARG_MAX is wrongly (or at least ambiguously) defined on my Mac Mini 3,1 running Ubuntu 12.04: $ getconf ARG_MAX # ...
3
votes
3answers
463 views

What is a “non-option argument”?

I am trying to understand info who but completly fail at the term »non-option argument«. Can someone please explain this term to me in simple words or an example? UPDATE: from ' info who' ...
0
votes
1answer
356 views

Pipe output from one command to another command's non standard input [duplicate]

I would like to do something similar to the following: which someapplciation | cd outputfrompreviouscommand The command which provides a directory and I would like to be able to make that output my ...
3
votes
5answers
1k views

How to use filename arguments or default to stdin, stdout (brief)

I want to handle filenames as arguments in a bash script in a cleaner, more flexible way, taking 0, 1, or 2 arguments for input and output filenames. when args = 0, read from stdin, write to stdout ...