I want to add the following line:
%optflags "-O2"
In a file a.txt using shell.
When I write:
{ echo "%optflags "-O2""
} >> a.txt
It prints:
%optflags -O2
How can I get this right?
Escape the double quotes:
echo "%optflags \"-O2\""
or
Use single quotes:
echo '%optflags "-O2"'
Note: you can partly see what was going on with your original code if you check it in bash -x:
$ echo "%optflags "-O2""
+ echo '%optflags -O2'
It passed a single argument to echo.. Why? Well, it concatenated "%optflags ", -O2, and "" (the empty string) to a single argument.
Related
Code snippet:
my $node = shift;
my $runCmd = "cmviewcl -v -f line -p ".$package_name." | awk -F \"[:|=]\" \'(\$1 == \"script_log_file\") { print \$2 }\'";
my $logfile = $output[0];
chomp $logfile;
#DC1_list = utils::getDC1Host($hash_ref);
#DC2_list = utils::getDC2Host($hash_ref);
foreach $node1 (#DC1_list) {
$runCmd = "cmexec $node1 echo \"\" > ".$logfile;
Please let me know the what's this line means:
$runCmd = "cmexec $node1 echo \"\" > ".$logfile;
it was written before as:
$runCmd = "cmexec $node1 rm -rf ".$logfile;
which probably means remove the file in logfile variable forced recursive, but later changed to the above. so
what's it's doing?
Remove a file is different than an empty file.
The first option keep the file but override the content with "" (2x double quote), the second one remove the file.
Maybe your application need the file exist, because of this you cannot remove it.
If you have really copied this line verbatim, it is pretty nonsense.
Let's assume that the variables mentioned here have the folllowing values:
runCmd has value FOO
node1 has value BAR
logfile has value BAZ
After parameter expansion and making the quoting a bit more legible, this leaves you with a line equivalent to
FOO = 'cmexec BAR echo "" >' .BAZ
This means that a command named FOO is invoked. It must either be an executable file in the PATH, or a function. This command gets three parameters:
First parameter : a lonely equal sign
Second parameter: The string cmexec BAR echo "" >
Third paramete : the string .BAZ
I don't believe that anybody would seriously write such a command; my guess is that you made a typo, or error when doing a copy&paste of this command.
I define a function in Makefile
define write_file
for i in $( seq 1 10 )
do
echo "1234567" >> "tmp/test.txt"
done
endef
And
pre:
mkdir -p exe tmp
${call write_file}
But when I make pre,I got error:
mkdir -p exe tmp
for i in
/bin/sh: 1: Syntax error: end of file unexpected
Each line of a make-recipe is a single command that make runs in a single
new shell. So you need to make the body of the macro write_file into a single
shell command.
In addition, make expands anything of the unescaped form $(....),
treating .... as a defined or undefined make expression. So in your
case, make expands $( seq 1 10 ) to nothing. To stop make doing
that and let the shell expand $( seq 1 10 ), you need to escape $ for make,
which you do by writing $$ instead. The same goes for any $ in a make-recipe
that you intend to be expanded by the shell.
Putting these points together, you want:
define write_file
for i in $$( seq 1 10 ); \
do \
echo "1234567" >> "tmp/test.txt"; \
done
endef
I am beginning in scripting and I am trying to write a script in bash. I need a script to write a sequence of several file names that are numbered from 1 to 50 inside one file. These are trajectory files from MD simulations. My idea was to write something like:
for valor in {1..50}
do
echo "
#!/bin/bash
catdcd -o Traj-all.dcd -stride 10 -dcd traj-$valor.dcd" > Traj.bash
exit
However, I just got one file with the following line:
#!/bin/bash
catdcd -o Traj-all.dcd -stride 10 -dcd traj-50.dcd
exit
But what I really want is something like:
#!/bin/bash
catdcd -o Traj-all.dcd -stride 10 -dcd traj-1.dcd -dcd traj-2.dcd -dcd traj-3.dcd ... -dcd traj-50.dcd
exit
How can I solve this problem?
You need to read a bit more about bash brace expansion. You can do this:
{
echo "#!/bin/bash"
echo "catdcd -o Traj-all.dcd -stride 10" "-dec traj-"{1..50}".dcd"
# ^^^^^^^^^^^^^^^^^^^^^^^^^
} > Traj.bash
The underlined part is where the brace expansion will get expanded by the shell into
-dec traj-1.dcd -dec traj-2.dcd ... -dec traj-50.dcd
You don't need to explicitly end your script with exit -- the shell will exit by itself when it runs out of commands.
> truncates the file on open. Either only use it once before the loop to create the file and then append (>>) within the loop, or redirect the entire loop.
> foo
for ...
do ...
echo ... >> foo
done
...
{
for ...
do ...
echo ...
done
} > foo
In Windows Command Line I normally write empty line in a file with
echo; >> file
However, what I have now is a variable
$param1%
If I want echo to write it in the file I have to do
echo %param1% >> file
HERE IS WHERE THE PROBLEM START :
If I'd like an empty like I'd make
set param1=;
However since the ; is not in contact with the echo word the command is
echo ; >> file
which write the ; in the file...
I need the variable to sometime contains text, and sometime nothing. How can I do it?
if "%param1%"=="" echo;>>file else echo %param1%>>file
If a param1 variable does not exist (the same as set "param1="), then %param1% results to:
In a .bat script: %param1% results to an empty string (a string of zero length);
In a CLI window: %param1% results to the %param1% string.
In a .bat script use (note no spaces surrounding %param1%)
>> file (echo;%param1%)
In a CLI window use
>>file (if not defined param1 (echo;) else echo;%param1%)
Note proper using of parentheses in if-else! For instance, check interesting result of next command:
if ""=="" echo;"THEN branch">>file else echo;"ELSE branch">>file
Output:
==>if ""=="" echo;"THEN branch">>file else echo;"ELSE branch">>file
==>type file
"THEN branch" else echo;"ELSE branch"
What I'm doing is: echo put $clientfilepath'client-'$clientversion-'.jar' >> ftp.ftp in a shell file.
Where $clientfilepath is: c:\\workspace\\project\\jack\\prj1\\target\\ and $clientversion is 1.0-snapshot
What I expect in ftp.ftp:
put
c:\\workspace\\project\\jack\\prj1\\target\\client-1.0-snapshot.jar
But what I'm getting is:
put c:\\workspace\\project\\jack\\prj1\\target\\
client-1.0-snapshot
.jar
I'm using double \ so nothing in the filepath should get treated as a special character.
So does anyone know what's happening?
echo put $clientfilepath'client-'$clientversion-'.jar'|tr '\n' '' >> ftp.ftp
You can simplify the quoting:
echo "put ${clientfilepath}client-${clientversion}-.jar" >> ftp.ftp
Try that to see if it helps with your problem. Also try printf instead of echo:
printf 'put %sclient-%s-.jar\n' "$clientfilepath" "$clientversion" >> ftp.ftp