I want to convert the following if statement to java, could someone explain to me what -a -a 5-lt 2 means. Is -a is like and?
if [ 4 -gt `echo "2+(3/2)" |bc` -a 5-lt 2]; then
Thank you Azad
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Azad Boss
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It's not an argument to `if` at all, it's an argument to `[`, which is a separate command. – Charles Duffy Jan 19 '16 at 17:45
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I am not quick understanding it. So, what does "-a 5-lt 2" means? – Azad Boss Jan 19 '16 at 18:22
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It has no meaning; it's invalid syntax and doesn't work. – Charles Duffy Jan 19 '16 at 18:24
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...now, if you mean `-a 5 -lt 2`, with the spaces, that means "and 5 is numerically less than 2", but it's a deprecated syntax that isn't supposed to be used. – Charles Duffy Jan 19 '16 at 18:25
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...the POSIX-compliant syntax is more like `if [ 4 -gt "$(echo "2+(3/2)" | bc)" ] && [ 5 -lt 2 ]; then` -- **with** all the spaces; none of them are optional. – Charles Duffy Jan 19 '16 at 18:26
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...whereas modern syntax for ksh or bash is more like `if (( 4 > "$(echo "2+(3/2)" | bc)" && 5 < 2 ))`. – Charles Duffy Jan 19 '16 at 18:28
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See BashPitfalls #10 at http://mywiki.wooledge.org/BashPitfalls#if_.5Bbar.3D.22.24foo.22.5D.3B_then_... -- actually, you might do well to read the whole document. – Charles Duffy Jan 19 '16 at 18:29
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Thank you, I understanding now. – Azad Boss Jan 19 '16 at 18:55