From $ man sh: "read [-p prompt] [-r] variable [...]". Is any default name for the requested variable?
I have omitted it by mistake, yet the script ran with no error, except the unexpected result, of course :) .
The default variable for POSIX shells is REPLY.
Related
I want to run this script:
#!/bin/bash
echo <(true)
I run it as:
sh file.sh
And I get "Syntax error: "(" unexpected" . I found some similar situations but still can't solve this.
I'm a beginner at shell scripting , but as I understand:
the shebang I use is correct and chooses the bash shell , so the process substitution syntax should work
I try the same from the command line and it works. I checked with echo $0 and it gives me "bash" , so what's the difference from running the command in the command line and from a script that invokes the same shell?
Maybe it's something simple, but I couldn't find an explanation or solution.
You should run your script with bash, i.e. either bash ./script.sh or making use of the shebang by ./script.sh after setting it to executable. Only running it with sh ./script.sh do I get your error, as commented by Cyrus.
See also: role of shebang at unix.SE
Remove export POSIXLY_CORRECT=1 from your ~/.bashrc or ~/.profile (etc.) files.
The issue is that process substitution is an added bash feature that is not part of the posix standards.
sh file.sh
errorsh: 3: Syntax error: "(" unexpected
solution:
bash file.sh
I want to run this script:
#!/bin/bash
echo <(true)
I run it as:
sh file.sh
And I get "Syntax error: "(" unexpected" . I found some similar situations but still can't solve this.
I'm a beginner at shell scripting , but as I understand:
the shebang I use is correct and chooses the bash shell , so the process substitution syntax should work
I try the same from the command line and it works. I checked with echo $0 and it gives me "bash" , so what's the difference from running the command in the command line and from a script that invokes the same shell?
Maybe it's something simple, but I couldn't find an explanation or solution.
You should run your script with bash, i.e. either bash ./script.sh or making use of the shebang by ./script.sh after setting it to executable. Only running it with sh ./script.sh do I get your error, as commented by Cyrus.
See also: role of shebang at unix.SE
Remove export POSIXLY_CORRECT=1 from your ~/.bashrc or ~/.profile (etc.) files.
The issue is that process substitution is an added bash feature that is not part of the posix standards.
sh file.sh
errorsh: 3: Syntax error: "(" unexpected
solution:
bash file.sh
I want to run this script:
#!/bin/bash
echo <(true)
I run it as:
sh file.sh
And I get "Syntax error: "(" unexpected" . I found some similar situations but still can't solve this.
I'm a beginner at shell scripting , but as I understand:
the shebang I use is correct and chooses the bash shell , so the process substitution syntax should work
I try the same from the command line and it works. I checked with echo $0 and it gives me "bash" , so what's the difference from running the command in the command line and from a script that invokes the same shell?
Maybe it's something simple, but I couldn't find an explanation or solution.
You should run your script with bash, i.e. either bash ./script.sh or making use of the shebang by ./script.sh after setting it to executable. Only running it with sh ./script.sh do I get your error, as commented by Cyrus.
See also: role of shebang at unix.SE
Remove export POSIXLY_CORRECT=1 from your ~/.bashrc or ~/.profile (etc.) files.
The issue is that process substitution is an added bash feature that is not part of the posix standards.
sh file.sh
errorsh: 3: Syntax error: "(" unexpected
solution:
bash file.sh
Same problem as this OP, but must be a seperate cause.
The following script:
#!/bin/sh
arr=("cat" "dog" "bird")
Works interactively (debian) but fails when called by crontab with:
/bin/sh: 2: /path/zero_check.sh: Syntax error: "(" unexpected
I've tried with #!/bin/bash shebang, and declaring array with declare -a arr=("cat" "dog" "bird"), to no effect.
Any idea why?
The problem here is that you are using this shebang:
#!/bin/sh
Whereas arrays are something Bash specific that shell does not allow.
So to make it work, change the shebang of your script to Bash:
#!/bin/bash
Specify your interpreter explicitly in the crontab entry. Use
bash /path/zero_check.sh
rather than
/path/zero_check.sh
Just for the documentation,
i had an old script to run which had an Syntax Error in the Shebang:
#/bin/bash
instead of
#!/bin/bash
Also check the Script is executable of course.
Very similar problem with incorrect bash function declarations. This works OK from the command line, but it causes cron to fail...
function test () { ... }
Cron should save the errors in /var/mail
I also recommend linting with "shellcheck" because it found another error I didn't notice.
This question already has answers here:
How do I syntax check a Bash script without running it?
(10 answers)
Closed 6 years ago.
The following shell script executes well when provided /bin/true for the first argument, but may otherwise fail with a syntax error during execution!
#!/bin/sh
if $1 ; then exit; fi
/tmp/asdf <<< ASDF # Something with syntax error in POSIX
Surely some syntax errors (if not all?) can be avoided by static checking? How do I statically check whether a given Shell Command Language script is syntactically valid?
EDIT: Checking for syntax errors in Bash scripts has been answered in this question.
EDIT #2: Note that Bash fails to properly check whether the syntax adheres to POSIX even when executed with the +B and --posix flags in addition to -n.
All POSIX-compatible Shell Command Language shells support the set -n built-in which can be used to check the syntax of the script. Therefore it is possible to prepend
set -n
to your code to syntax check it. Note also that standard sh utility is also required to support a command-line -n flag, which has equivalent semantics to using set -n. Bash and possibly other shells also support this command-line flag. Therefore you can simply run the following to syntax check your script:
sh -n yourScriptFilename.sh
WARNING: This does not give you a guarantee that the script has fully POSIX compatible syntax. For example, Bash allows bashisms (e.g. arrays and c{a,u}t) to go unnoticed even when using the --posix (and/or +B) command line option in addition to -n when invoked as sh. Other shells might have similar issues.
With bash you can use -n:
bash -n file.sh
Output:
a.sh: line 3: syntax error near unexpected token `then'
a.sh: line 3: `if then fi # Something with syntax error'
Since bash supports the --posix options you may run
bash --posix -n file.sh
to perform a posix compatible check. I don't know how posixly correct that mode is in detail.