====== Use Input-output Redirection ======
**General Information**
Using input/output redirection (>, >>, |, 2>, etc.).
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'>' Redirect standard output to a file, overwrite contents
cat /etc/system-release > info.txt
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'>>' Redirect standard output to file, append to file
tail /etc/passwd >> info.txt
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'|' Piping output to other commands
cat /etc/passwd | wc -l
* Counts the number of lines in /etc/passwd
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'2>' Redirect standard error
ssh admin@webserver01.com "uptime" 2>/dev/null
* SSH to webserver01.com, issue the uptime command, send standard errors to /dev/null (to nowhere)
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Redirect both standard error and standard output
ssh admin@webserver01.com "uptime" &> results.log
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Redirect standard error to standard out
cat /etc/system-release /etc/Red 2>&1 | grep Red
* Standard output can be passed through a pipe to the next command. By redirecting standard error to standard output, any error messages are successfully sent through as well.
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