Question

I need to compare strings in shell:

var1='mtu eth0'  if [ '$var1' == 'mtu *' ] then     # do something fi 

But obviously the ‘*’ doesn’t work in Shell. Is there a way to do it?

Answer 1

bash

Shortest fix:

if [[ '$var1' = 'mtu '* ]] 

Bash’s [[ ]] doesn’t get glob-expanded, unlike [ ] (which must, for historical reasons).

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bash --posix

Oh, I posted too fast. Bourne shell, not Bash…

if [ '${var1:0:4}' == 'mtu ' ] 

${var1:0:4} means the first four characters of $var1.

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/bin/sh

Ah, sorry. Bash’s POSIX emulation doesn’t go far enough; a true original Bourne shell doesn’t have ${var1:0:4}. You’ll need something like mstrobl’s solution.

if [ '$(echo '$var1' | cut -c0-4)' == 'mtu ' ]