Page Comparison

This page should serve as a reference for the many "things Linux" we use in this course. It is by no means complete – Linux is **huge** – but offers introductions to many important topics.

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• Macs and Linux have a Terminal program built-in
• Windows options:
  • Windows 10+
    • Command Prompt and PowerShell programs have ssh and scp (may require latest Windows updates)
      • Start menu → Search for Command
    • Putty – http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
      
      • simple Terminal and file copy programs
      • download either the Putty installer or just putty.exe (Terminal) and pscp.exe (secure copy client)
    • Windows Subsystem for Linux – Windows 10 Professional includes a Ubuntu-like bash shells
      • See https://docs.microsoft.com/en-us/windows/wsl/install-win10
      • We recommend the Ubuntu Linux distribution, but any Linux distribution will have an SSH client

Use ssh (secure shell) to login to a remote computers.

# General form:
ssh <user_name>@<full_host_name>

# For example
ssh abattenh@ls6.tacc.utexas.edu

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nums=$( seq 5 )
echo $nums
echo "$nums"

echo $nums| wc -l     # newlines converted to spaces, so only one line
echo "$nums" | wc -l  # newlines preserved, so reports 5

# This loop prints a line for each of the files
for n in $nums; do
  echo "the number is: '$n'"
done

# But this loop prints only one line
for n in "$nums"; do
  echo "the number is: '$n'"
done

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the if statement

The general form of an if/then/else statement in bash is:

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A good reference on the many built-in bash conditionals: https://www.gnu.org/software/bash/manual/html_node/Bash-Conditional-Expressions.html

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reading file lines with while

The read function can be used to read input one line at a time, in a bash while loop.

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