HPC Linux Tutorial

Software Carpentry's Unix Shell Lesson

Software Carpentry focuses on teaching researchers the computing skills they need to get more done in less time and with less pain. Their lesson on the Unix Shell is listed below. Note that while they refer to it as Unix, the lesson also applies to its younger cousin Linux.

• The Unix Shell Lesson
• Unix Shell Summary of Basic Commands Reference

Ryan's Tutorials

Ryan's Tutorials are also excellent. Two relevant tutorials are linked below.

• Linux Tutorial
• Bash Scripting Tutorial

On-line Manual Pages

Linux consists of thousands of commands. While the command options arguments syntax is common among most of them, it can be daunting to remember the various options for each command. Options don't necessary have the same meaning between different commands. For example, the -i option has a different meaning when used with ls than with grep. To eliminate the need to keep a thick Linux command "bible" next to you at all times (or more likely a browser window open to your favorite search engine), the system provides "manual pages" built into Linux that can be called up as needed. These are called man pages in Linux lingo. You use the man command to display the manual pages for a command, e.g. man cat will display the manual page for the cat command.

Let's review an example man page.

$ man cat

CAT(1)                                                            User Commands                                                           CAT(1)



NAME
       cat - concatenate files and print on the standard output

SYNOPSIS
       cat [OPTION]... [FILE]...

DESCRIPTION
       Concatenate FILE(s), or standard input, to standard output.

       -A, --show-all
              equivalent to -vET

       -b, --number-nonblank
              number nonempty output lines, overrides -n

       -e     equivalent to -vE

       -E, --show-ends
              display $ at end of each line

       -n, --number
              number all output lines

       -s, --squeeze-blank
              suppress repeated empty output lines

       -t     equivalent to -vT

       -T, --show-tabs
              display TAB characters as ^I

       -u     (ignored)

       -v, --show-nonprinting
              use ^ and M- notation, except for LFD and TAB

       --help display this help and exit

       --version
              output version information and exit

       With no FILE, or when FILE is -, read standard input.

EXAMPLES
       cat f - g
              Output f's contents, then standard input, then g's contents.

       cat    Copy standard input to standard output.

       GNU coreutils online help: <http://www.gnu.org/software/coreutils/> Report cat translation bugs to <http://translationproject.org/team/>

AUTHOR
       Written by Torbjorn Granlund and Richard M. Stallman.

COPYRIGHT
       Copyright © 2013 Free Software Foundation, Inc.  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
       tac(1)

       The  full documentation for cat is maintained as a Texinfo manual.  If the info and cat programs are properly installed at your site, the
       command

              info coreutils 'cat invocation'

       should give you access to the complete manual.



GNU coreutils 8.22                                                November 2015                                                           CAT(1)

$ man -k concatenate

g3cat (1)            - concatenate multiple g3 documents
strcat (3)           - concatenate two strings
strncat (3)          - concatenate two strings
wcscat (3)           - concatenate two wide-character strings
wcsncat (3)          - concatenate two wide-character strings
cat (1)              - concatenate files and print on the standard output
cat (1p)             - concatenate and print files
nc (1)               - Concatenate and redirect sockets
ncat (1)             - Concatenate and redirect sockets
pmlogextract (1)     - reduce, extract, concatenate and merge Performance Co-Pilot archives
strcat (3p)          - concatenate two strings
strncat (3p)         - concatenate a string with part of another
tac (1)              - concatenate and print files in reverse
Tcl_Concat (3)       - concatenate a collection of strings
wcscat (3p)          - concatenate two wide-character strings
wcsncat (3p)         - concatenate a wide-character string with part of another
zcat (1p)            - expand and concatenate data