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BeMy Friend
Asked: 2015-03-18 16:28:19 +0800 CST

Bash - IF and && syntax?

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I could use a little help with my IF and && statement. It's not working and nothing I'm trying is working either. Maybe someone can see the issue:

if [[ $thisvariable="yes" && grep 'this string' ./"$thisfile".txt ]]; then

This just doesn't work. Does anyone see an issue?

bash

4 Answers

  1. Try this:

    if [[ "$thisvariable" = "yes" ]] && grep -q 'this string' ./"${thisfile}".txt; then
    • 1

  2. I'm just now seeing the last post, so I didn't try that. I finally got it to work with this:

    if [ $thisvariable == yes ] && [ "`grep 'this string' ./"thisfile"`" ]; then
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  3. The [ construct cannot take multiple conditions. What you are attempting can be written in multiple ways:

    if [ "$thisvariable" = "yes" ] && grep 'this string' ./"thisfile" > /dev/null
then 
    echo yes; 
fi

    or, more simply

    [ "$thisvariable" = "yes" ] && grep 'this string' ./"thisfile" > /dev/null && echo yes
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  4. From: http://tldp.org/LDP/abs/html/comparison-ops.html#SCOMPARISON1

    if [ "$a" = "$b" ]

    Caution!, note the whitespace framing the "=".

    if [ "$a"="$b" ] is not equivalent to the above.
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