Redirection of output and input in unix/linux
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This document discusses different types of shells, their features, and configuration files. It also covers redirection of input/output in shells. There are several common shells like Bourne, C, TC, Korn, and Bash that vary in their features such as command history, aliases, scripting abilities. Configuration files configure shells and are read during login or interactively. Redirectors like >, >>, <, 2>, 2>&1 are used to control input/output streams and send them to files. Examples show how redirection is used for various purposes like logging output and errors separately.
Redirection of output and input in unix/linux
- 1. Created by
- 2. TopicsSHELL1Different types of shell
- 3. Summary of shell features
- 4. Configuration files for shellsREDIRECTION OF OUTPUT AND INPUT 2Redirect descriptor
- 5. Redirect usage12Different types of shellShellPathDescriptionOSBourne/bin/shThis is the original Unix shell written by Steve Bourne of Bell Labs. It is available on all UNIX systems.All unixKorn/bin/kshThis shell was written by David Korn of Bell labs. It is now provided as the standard shell on Unix systems.AIXC/bin/cshThis shell was written at the University of California, Berkeley. It provides a C-like language with which to write shell script.BSDTC/bin/tcshThis shell is available in the public domain. It provides all the features of the C shell together with emacs style editing of the command line.MAC OSXBash/bin/bashThis is a public domain shell written by the Free Software Foundation under their GNU initiative.Ubuntu, CentosReference: http://unixhelp.ed.ac.uk/shell/oview2.html
- 6. TopicsSHELL1Different types of shell
- 7. Summary of shell features
- 8. Configuration files for shellsREDIRECTION OF OUTPUT AND INPUT 2Redirect descriptor
- 9. Redirect usage12Summary of shell features BourneCTCKornBashCommand historynoyesyesyesyesCommand aliasnoyesyesyesyesShell scripts yesyesyesyesyesFilename completion noyes*yesyes*yesCommand line editing nonoyesyes*yesJob control noyesyesyesyes* Not the default setting for this shell.Reference: http://unixhelp.ed.ac.uk/shell/oview1.1.html
- 10. TopicsSHELL1Different types of shell
- 11. Summary of shell features
- 12. Configuration files for shellsREDIRECTION OF OUTPUT AND INPUT 2Redirect descriptor
- 13. Redirect usage12Configuration files for shellsshkshcshtcshbash/etc/.loginloginlogin/etc/csh.cshrcyesyes/etc/csh.loginloginlogin~/.tcshrcyes~/.cshrcyesyes~/.loginloginlogin~/.logoutloginlogin/etc/profileloginloginlogin~/.profileloginloginlogin~/.bash_profilelogin~/.bash_loginlogin~/.bash_logoutlogin~/.bashrcint. + n/login blank means a file is not read by a shell at all."yes" means a file is always read by a shell upon startup."login" means a file is read if the shell is a login shell."n/login" means a file is read if the shell is not a login shell."int." means a file is read if the shell is interactive.Reference: http://en.wikipedia.org/wiki/Unix_shell
- 14. TopicsSHELL1Different types of shell
- 15. Summary of shell features
- 16. Configuration files for shellsREDIRECTION OF OUTPUT AND INPUT 2Redirect descriptor
- 17. Redirect usage12Redirect descriptorDescriptorDescription0Standard Input (Generally Keyboard)1Standard output (Generally Display/Screen)2Standard Error Ouput (Generally Display/Screen)>Redirect standard output2>Redirect standard error2>&1Redirect standard error to standard output<Redirect standard input from>>Append to standard output&Run as background process
- 18. TopicsSHELL1Different types of shell
- 19. Summary of shell features
- 20. Configuration files for shellsREDIRECTION OF OUTPUT AND INPUT 2Redirect descriptor
- 21. Redirect usage12Redirect usageLet me write the example about how to use redirection in various purpose.Redirect standard output to a file #!/bin/bash/home/panu/start-application1.sh > fileAppend standard output to a file #!/bin/bash/home/panu/start-application1.sh >> fileRedirect standard input from file#!/bin/bash/home/panu/start-application1.sh < fileRedirect standard output to “std_out.log” and redirect standard error to “std_error.log”#!/bin/bash/home/panu/start-application1.sh > std_out.log 2> std_err.logRedirect standard error to standard output “std_out_err.log”#!/bin/bash/home/panu/start-application1.sh > std_out_err.log 2>&1
- 22. Thank you for watchingmy presentationCreated bypanuausavasereelertblog: http://panu.in.themail: panu@panu.in.thtwitter: @panuinth