Tagged Questions

7
votes
1answer
129 views

“w | tail” chops text at right margin (78 characters)

Summary: w | tail chops rows after 78th column. When I run the "w" command, it works as expected. However, when I pipe the output to "tail", it chops the output to 78 columns wide (truncates anything ...
0
votes
1answer
136 views

Can someone provide an xargs example piping mysql query data into another command?

Can someone provide an example for the command xargs? I want to do a mysql query to return the ID field of a column then feed that result into xargs into another command say mysql query delete. How ...
2
votes
1answer
335 views

Bash vs ksh pipes

I am stuck with some problems with my scripts in ksh. FWIW the problem which I am unable to overcome is that when I use a structure such as this command | while read VAR1 do many.commands using ...
1
vote
2answers
296 views

Print/Tee to console without passing output to pipe

Is there a way to print or tee one thing to the console and still pass something else through to the next pipe? Something like: echo dog | printOrWhatnot "PUTTING MY THING DOWN" | sed 's/dog/cat/g' | ...
0
votes
1answer
155 views

The “cp p2 &2 &” command makes Konsole to disappear, is it a bug?

The goal is start a background process that copies the data from the pipe p2 to the STDOUT as p2 is feed with data by some other process. I guess the command is incorrect. Nevertheless, the Konsole ...
7
votes
4answers
556 views

What is the easiest way to execute text from tail at the command line?

Sometimes I'm working on a new (ubuntu) box and I type git and am alerted: The program 'git' is currently not installed. You can install it by typing: apt-get install git-core If that happens I ...
2
votes
1answer
255 views

Keep global variables values piping through functions

I wrote a little bash script using sed on some html pages to extract some urls. To avoid each time grabbing sed results in a variable then read it again I simply made 3 functions and piped together. ...
2
votes
2answers
529 views

How can I retain the console input in mplayer when reading from stdin?

I'm playing around with the command line interface of mplayer. I'd like to script it in the following way find /some/path/ -type f | grep -vif blacklist | mplayer -shuffle -playlist - where ...
6
votes
2answers
917 views

bash: Piping for loop output prevents local variable modification

First off, sorry for the title. I'm not sure of the correct terminology so if anyone can improve upon it that would be good. I am trying to write a simple bash function that takes, as it's arguments, ...
17
votes
2answers
507 views

Should I care about unnecessary cats?

A lot of command-line utilities can take their input either from a pipe or as a filename argument. For long shell scripts, I find starting the chain off with a cat makes it more readable, especially ...
4
votes
3answers
2k views

Why is my variable being localized in one 'while read' loop, but not in another seemingly similar loop

Why do I get different values for $x from the snippets below? #!/bin/bash x=1 echo fred>junk ; while read var ; do x=55 ; done <junk echo x=$x # x=55 .. I'd expect this result x=1 cat ...