Revisions to Conditional pipeline

no need to be ksh (or bash or zsh) specific to make this valuable point.

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edited Feb 5, 2013 at 21:57

ifif/elseelse/fifi works. Assuming bash or zshany Bourne-like shell:

cmd1 < input.txt |
cmd2 |
if [[[ -n $DEFINED"$DEFINED" ]];]; then cmd3; else cat; fi |
cmd4 |
cmd5 |
cmd6 |
(...) |
cmdN > result.txt

if/else/fi works. Assuming bash or zsh:

cmd1 < input.txt |
cmd2 |
if [[ -n $DEFINED ]]; then cmd3; else cat; fi |
cmd4 |
cmd5 |
cmd6 |
(...) |
cmdN > result.txt

if/else/fi works. Assuming any Bourne-like shell:

cmd1 < input.txt |
cmd2 |
if [ -n "$DEFINED" ]; then cmd3; else cat; fi |
cmd4 |
cmd5 |
cmd6 |
(...) |
cmdN > result.txt

Backslash not needed when last char on a line

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edited Oct 23, 2012 at 11:28

if/else/fi works. Assuming bash or zsh:

cmd1 < input.txt |\|
cmd2 |\|
if [[ -n $DEFINED ]]; then cmd3; else cat; fi |\|
cmd4 |\|
cmd5 |\|
cmd6 |\|
(...) |\|
cmdN > result.txt

if/else/fi works. Assuming bash or zsh:

cmd1 < input.txt |\
cmd2 |\
if [[ -n $DEFINED ]]; then cmd3; else cat; fi |\
cmd4 |\
cmd5 |\
cmd6 |\
(...) |\
cmdN > result.txt

if/else/fi works. Assuming bash or zsh:

cmd1 < input.txt |
cmd2 |
if [[ -n $DEFINED ]]; then cmd3; else cat; fi |
cmd4 |
cmd5 |
cmd6 |
(...) |
cmdN > result.txt

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answered May 10, 2012 at 8:03

if/else/fi works. Assuming bash or zsh:

cmd1 < input.txt |\
cmd2 |\
if [[ -n $DEFINED ]]; then cmd3; else cat; fi |\
cmd4 |\
cmd5 |\
cmd6 |\
(...) |\
cmdN > result.txt

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