Bash: Piping Text

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Aron Schatz

2014: Year of change. Joined: August 3, 2001 Status: Offline Posts: 10753 Rep:

Bash: Piping Text

Sun Aug 27, 2006 8:37:07 AM #22099 Perm Link

I completely forgot how to pipe text from a command to another command...

I want to take the 'uptime' command response and pipe that to a variable (or directly) and then call ./lcdsetup -c 1 -t $1

$1 would be the response to uptime. I'm sure this is easy Wink

2014 is going to be a good year. More content, more streamlining. Be a part of history!

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free::zombie

Joined: December 6, 2005 Status: Offline Posts: 930 Rep:

(No Title)

Sun Aug 27, 2006 9:52:17 AM #22108 Perm Link

Code

### piping crash course ###

var=`command` # put output of 'command' into $var
var=$(command) # same as above, but can be nested. Non-standard but works in major shells
command1 | command2 # feed standard output of 'command1' to standard input of 'command2'
command > file # overwrite file 'file' with output of 'command'
command >>file # append output of 'command' to file 'file'
command < file # feed file 'file' to standard input of 'command'

# now, the handy "heredoc"
command << "MARKER" # feed everything until MARKER (can be anything, traditionally it is EOF)
blah # to 'command'. this is useful in scripts where you want to give a program
blah # some input automatically without dequiring the user to type
MARKER # :)

# the "pipe" | can be used with a variaty of UNIX programs, for example grep, sed, awk, head, tail and diff.
# redirecting output to a file ( >file ) can be used to supress output: command >/dev/null
# (the UNIX pseudo-device /dev/null swallows all input and outputs only ASCII EOF)

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Aron Schatz

2014: Year of change. Joined: August 3, 2001 Status: Offline Posts: 10753 Rep:

(No Title)

Mon Aug 28, 2006 9:40:48 AM #22129 Perm Link

In response to free::zombie #22108

Thanks for the help free-zombie.

If anyone has any problems with Bash, zombie is the guy to talk to.

2014 is going to be a good year. More content, more streamlining. Be a part of history!

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