Re: [CentOS] bash off topic
So others have commented about the particulars of bash and shell quotes, etc. I wanted to suggest you take a look at ShellCheck [1,2] and BATS [3]. I have been doing syntax, lint, and acceptance testing for Puppet code for about a year...and love it... but I recently came across these and have been working to apply the same principles to my shell script projects. The sheer number of fringe bugs in my script that using shellcheck has lead me to clean up has been amazing. BATS is more complicated, but the principle is that you write tests that can assert that your script is working or not. So I made a project just to play with this stuff, if you want to check it out [4]. [1] http://shellcheck.net [2] https://github.com/koalaman/shellcheck [3] https://github.com/bats-core/bats-core [4] https://gitlab.com/salderma/bash-spec-test --Sean > > From: Jerry Geis > To: CentOS mailing list > Cc: > Bcc: > Date: Thu, 16 May 2019 12:57:43 -0400 > Subject: [CentOS] bash off topic > I have a simple bash script it will take arguments from a file that has > quotes. > > my file arg.txt would be this > -lt "*.txt" > > my script file would be > LS_ARG=`cat arg.txt` > ls $LS_ARG > > it does not run properly: > sh -x ./arg.sh > ++ cat arg.txt > + LS_ARG='-lt "*.txt"' > + ls -lt '"*.txt"' > ls: cannot access "*.txt": No such file or directory > > > How do I resolve that ? If the quotes are not in my file it all works > fine. I think its because it looks like the extra single quotes it puts > around the "*.txt" - or - '"*.txt"' - how do I do this ? This is just a > short example of my larger need. > > Thanks, > > Jerry > > ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] bash off topic
On Thu, 2019-05-16 at 12:57 -0400, Jerry Geis wrote: > I have a simple bash script it will take arguments from a file that has > quotes. > > my file arg.txt would be this > -lt "*.txt" > > my script file would be > LS_ARG=`cat arg.txt` > ls $LS_ARG > > it does not run properly: > sh -x ./arg.sh > ++ cat arg.txt > + LS_ARG='-lt "*.txt"' > + ls -lt '"*.txt"' > ls: cannot access "*.txt": No such file or directory > > > How do I resolve that ? If the quotes are not in my file it all works > fine. I think its because it looks like the extra single quotes it puts > around the "*.txt" - or - '"*.txt"' - how do I do this ? I think it's to do with when the wildcard * is expanded. The expansion is not done by 'ls', it is done by the shell - so when you do 'ls *', ls doesn't see just the single argument '*', it sees multiple arguments consisting of the filenames. Using a simpler example, a shell script 'c' is: #!/bin/bash echo $# echo "1:" $1 echo "2:" $2 i.e. it displays the number of and the first two arguments: $ ./c * 4 1: a 2: a2 So there are 4 arguments (not just one) because there are four files in the directory. You can turn off the expansion (aka globbing) with 'set -f' $ set -f ; ./c * ; set +f 1 1: * 2: (But you also have to turn off globbing in the './c' script as well - that's a subshell and globbing isn't inherited #!/bin/bash set -f echo $# echo "1:" $1 echo "2:" $2 if you don't turn off globbing in the script, when $1 - which contains '*' - is echoed, it is expanded at that point.) Putting quotes around the "*" stops the expansion - this is with globbing turned off in the script: $ ./c "*" 1 1: * 2: Similarly, using ls: $ ls * a a2 arg.txt c $ set -f ; ls * ; set +f ls: cannot access '*': No such file or directory $ ls "*" ls: cannot access '*': No such file or directory I don't know how this affects what you are trying to do though! BTW, the single quotes you see when tracing the shell script is, I think, just for display purposes, they aren't actually part of the variables and are there just to show what is a single entity if there is any doubt. P. ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] bash off topic
On Thu, 16 May 2019, Jerry Geis wrote: I have a simple bash script it will take arguments from a file that has quotes. my file arg.txt would be this -lt "*.txt" my script file would be LS_ARG=`cat arg.txt` ls $LS_ARG it does not run properly: sh -x ./arg.sh ++ cat arg.txt + LS_ARG='-lt "*.txt"' + ls -lt '"*.txt"' ls: cannot access "*.txt": No such file or directory How do I resolve that ? If the quotes are not in my file it all works fine. I think its because it looks like the extra single quotes it puts around the "*.txt" - or - '"*.txt"' - how do I do this ? This is just a short example of my larger need. In general, shell utilities won't expand a wildcard within quotes (double or single). As I think you've discovered, this works fine: echo '-lt *.txt' > argfile ls $(< argfile) I think you're going to need to provide a test case where the quotes are actually required. -- Paul Heinlein heinl...@madboa.com 45°38' N, 122°6' W ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS] bash off topic
I have a simple bash script it will take arguments from a file that has quotes. my file arg.txt would be this -lt "*.txt" my script file would be LS_ARG=`cat arg.txt` ls $LS_ARG it does not run properly: sh -x ./arg.sh ++ cat arg.txt + LS_ARG='-lt "*.txt"' + ls -lt '"*.txt"' ls: cannot access "*.txt": No such file or directory How do I resolve that ? If the quotes are not in my file it all works fine. I think its because it looks like the extra single quotes it puts around the "*.txt" - or - '"*.txt"' - how do I do this ? This is just a short example of my larger need. Thanks, Jerry ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
