WebJun 19, 2013 · invalid null command #! /bin/csh set pattern = "" set deli = foreach i ( `cat pattern`) set pattern = "$pattern$deli$i" end all i want to accomplish is create a string a b c, but instead I got an invalid null command error, thanks for your help 9. Shell Programming and Scripting Invalid Command Name WebAug 23, 2014 · The echo -n way is equivalent in its effects but arguably is a better solution, in that it's simpler. cat /dev/null > file opens three "files": The cat executable (usually /bin/cat ), a regular file. The /dev/null device. file. In contrast, echo -n > file opens only file ( echo is a shell builtin). Although this should be expected to improve ...
command line - What does 2>/dev/null mean? - Ask Ubuntu
http://easck.com/cos/2024/0923/337933.shtml WebApr 6, 2014 · @WinEunuuchs2Unix Not necessarily irrelevant - in some cases you want to ensure there's actually something instead of blank or null string in arguments. $1 could be unset or set to null string by user of the script. Consider this sequence of command: $ set '' bar then echo "x$ {1}x"; Both variables are set, but one of them is null. can you burp with your mouth closed
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WebMar 25, 2014 · 34 IF I have to check that if a variable is empty or not for that in bash shell i can check with the following script: if [ -z "$1" ] then echo "variable is empty" else echo "variable contains $1" fi But I need to convert it into tcsh shell. csh tcsh Share Improve this question Follow edited Mar 25, 2014 at 16:11 glenn jackman 235k 38 221 348 WebApr 20, 2015 · Csh is brain-dead sometimes, but it does have a built-in way to test if a variable is empty. – Gilles 'SO- stop being evil' Apr 21, 2015 at 1:04. I missed the double … WebJul 11, 2013 · Top Forums Shell Programming and Scripting If condition to check null variable # 1 07-11-2013 AraR87 Registered User 53, 2 If condition to check null variable Guys, Please help me on the below Code: sample.cfg var=NULL Code: sample.sh #!/bin/sh . /sample.cfg if [ $var -eq NULL ];then 1 st command here else 2 nd command here fi briggs and stratton dealer exam study guide