Bash
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Swapping stdin and stdout
command 3>&1 1>&2 2>&3
extracting vars from strings
example 1:
#!/usr/bin/env bash str1="the value of var1=test, the value of var2=testing, the final value of var3=testing1" re='(^|[[:space:]])([[:alpha:]][[:alnum:]]*)=([^, ]+)([, ]|$)(.*)' remaining=$str1 while [[ $remaining =~ $re ]]; do varname=${BASH_REMATCH[2]} value=${BASH_REMATCH[3]} remaining=${BASH_REMATCH[5]} printf -v "$varname" %s "$value" done # show current values to demonstrate that variables were really assigned declare -p var1 var2 var3
example 2:
extract the --port=XX section from what was handed to the script, where XX is a number.
#!/bin/bash #re="--port=(.*?) " re="--port=([0-9]*?) " if [[ $@ =~ $re ]]; then echo "match" echo zero ${BASH_REMATCH[0]} echo one ${BASH_REMATCH[1]} echo two ${BASH_REMATCH[2]} echo three ${BASH_REMATCH[3]} else echo "no match" fi