How could I set ant property the value which is the result of bash script execution? For example, I need to have target which utilizes svn and bash utilities in order to control build execution. Speaking more specifically, target that I'm trying to create will be used to define, whether there are modified files in deployed application via command:
svn stat | awk -F '' ' $1=="A" || $1 == "C" || $1=="M" || $1 == "D" || $1 == "R" {print $1}' | wc -l
I need to set the result of this command to some ${modified_lines_number} property.
Assuming you're using the exec task to run that command, that task has an outputproperty attribute that lets you specify the name of a property in which to store the output.
You could capture the output of your command like this:
OUTPUT=$(snv stat | ... | wc -l)
...and define a property for ant like this:
ant -Dmodified_lines_number=$OUTPUT
Related
how do i store the output of a command into a variable for use in a github-actions .yaml?
docker images --format='{{.ID}}' | select -first 1
gives me:
fc6e040841a1
i've seen stuff online about select-object..but i honestly have no idea, just trying to push an image to a registry...
the following cmd doesn't work in powershell:
for /f "delims=" %a in ("docker images --format='{{.ID}}' | select -first 1") do #set "%_img%=%a"
the following cmd doesn't work in powershell:
for /f "delims=" %a in ("docker images --format='{{.ID}}' | select -first 1") do #set "%_img%=%a"
That's because this is Command Prompt syntax. Specifically, everything outside of the () would only work under cmd.exe. The PowerShell equivalent for assigning a command result to a variable is:
$variableName = COMMAND
To apply it to your use case:
$imageId = docker images --format='{{.ID}}' | Select-Object -First 1
Note that select is an alias of Select-Object and either can be used interchangeably.
Edit: While not required for setting variables unlike in the Command Prompt, for syntax is still different in PowerShell when batch scripting. You can read up on PowerShell's for, foreach, and ForEach-Object constructs when you want to learn how they are used in PowerShell scripts, and watch for this gotcha when using the foreach "statement" as part of a pipeline.
While not part of the original scope of the question, since OP did ask and I answered in the comments, I will put the bash equivalent here for the sake of completeness and how I transposed this from the PowerShell method I used above:
imageId=$(docker images --format="{{.ID}}" | head -n 1)
This is similar to the PowerShell syntax with a few changes: remove the $ from the variable name on assignment, and Select-Object is replaced by head. You can't pad the = with whitespace, and you have to subshell the command with $().
I'd like to write a bit of code that looks like this:
while ( `ls -1 ${JOB_PREFIX}_${job_counter}_*.out | wc -l` > 0 )
echo "Do something here."
end
But every time there is no ls -1 ${JOB_PREFIX}_${job_counter}*.csh it gives an annoying ls: No match.
Is it possible to suppress this error message but still pipe STDOUT to wc ? I went through the existing questions on this but most of the answers are either not working on csh or tries to combine STDOUT and STDERR with |& which I do not want.
The cleanest way would have been to mute the ls itself, but it is not possible.
You can suppress your entire script, meaning:
If your loops is in a file called myscript.cs and you call your file with some args myscript.cs -arg1 blabla -arg2 bla, add >& to your shell command to redirect stderr to wherever you want. e.g.
myscript.cs -arg1 blabla -arg2 bla >& /dev/null
It's not answering your answer directly, but it should solve your problem.
Edit
Since the comment added that the script should be redirected to another script, you can split your line to two lines:
if `ls -1 ${JOB_PREFIX}_${job_counter}_*.out >& /dev/null` then
while < your while here >
end
endif
csh and tcsh cannot redirect stderr by itself, one of many reasons you should not use it for scripting.
If you're okay with spawning another shell, you can change JOB_COUNTER into an environment variable and do:
while ( `sh -c '2>/dev/null ls -1 ${JOB_PREFIX}_${JOB_COUNTER}_*.out | wc -l'` > 0 )
echo "Do something here."
end
If you want to use a test as a condition in a while loop instead of an expression, you have to get creative.
#!/bin/tcsh -f
set i = 4
while ( 1 )
if ( $i <= 0 ) break
echo hi
# i = ($i - 1)
end
In your case, this might look something like: I changed the wc -l to a grep -q . so that we can use the exit status instead of the result printed to stderr.
#!/bin/tcsh -f
set dir_exit_status = 0
while ( $dir_exit_status = 0 )
( ls -1 ${JOB_PREFIX}_${job_counter}_*.out | grep -q '.') >& /dev/null
set dir_exit_status = $status
end
I've got a small script called "onewhich". Its purpose is to behave like which, except that it will only give the FIRST occurrence of any executables specified as options, as found in the order they'd appear in the path.
So for example, if my path is /opt/bin:/usr/bin:/bin, and I have both /opt/bin/runme and /usr/bin/runme, then the command onewhich runme would return /opt/bin/runme.
But if I also have a /usr/bin/doit, then the command onewhich doit runme would return /usr/bin/doit instead.
The idea is to walk through the path, check for each executable specified, and if it exists, show it and exit.
Here's the script so far.
#!/bin/sh
for what in "$#"; do
for loc in `echo "${PATH}" | awk -vRS=: 1`; do
if [ -f "${loc}/${what}" ]; then
echo "${loc}/${what}"
exit 0
fi
done
done
exit 1
The problem is, I want to be better about PATH directories with special characters. Every second shell question here on StackOverflow talks about how bad it is to parse paths with tools like awk and sed. There's even a bash faq entry about it. (Proviso: I'm not using bash for this, but the recommendation is still valid.)
So I tried rewriting the script to separate paths in a pipe, like this"
#!/bin/sh
for what in "$#"; do
echo "${PATH}" | awk -vRS=: 1 | while read loc ; do
if [ -f "${loc}/${what}" ]; then
echo "${loc}/${what}"
exit 0
fi
done
done
exit 1
I'm not sure if this gives me any real advantage (since $loc is still inside quotes), but it also doesn't work because for some reason, the exit 0 seems to be ignored. Or ... it exits something (the sub-shell with the while loop that terminates the pipe, maybe), but the script exits with a value of 1 every time.
What's a better way to step through directories in ${PATH} without the risk that special characters will confuse things?
Alternately, am I reinventing the wheel? Is there maybe a way to do this that's built in to existing shell tools?
This needs to run in both Linux and FreeBSD, which is why I'm writing it in Bourne instead of bash.
Thanks.
This doesn't directly answer your question, but does eliminate the need to parse PATH at all:
onewhich () {
for what in "$#"; do
which "$what" 2>/dev/null && break
done
}
This just calls which on each command on the input list until it finds a match.
To parse PATH, you can simply set `IFS=':'.
if [ "${IFS:-x}" = "${IFS-x}" ]; then
# Only preserve the value of IFS if it is currently set
OLDIFS=$IFS
fi
IFS=":"
for f in $PATH; do # Do not quote $PATH, to allow word splitting
echo $f
done
if [ "${OLDIFS:-x}" = "${OLDIFS-x}" ]; then
IFS=$OLDIFS
fi
The above will fail if any of the directories in PATH actually contain colons.
Your first method looks to me as if it should work. In practical terms, if it's really the $PATH you'll be searching, it's unlikely you'll have spaces and newlines embedded in directories there. If you do, it's probably time to refactor.
But still, I don't think you're at risk from the possibility of bad names clobbering your loop, since you're wrapping variables in quotes. At worst, I suspect you might miss the odd valid executable, but I can't see how the script would generate errors. (I don't see how the script would miss valid executables, and I haven't tested - I'm just saying I don't see problems at first glance.)
As for your second question, about the loop, I think you've hit the nail on the head. When you run a pipe like this | that | while condition; do things; done, the while loop runs in its own shell at the end of the pipe. Exiting that shell may terminate the actions of the pipe, but that only brings you back to the parent shell, which has its own thread of execution that terminates with exit 1.
As for a better way to do this, I would consider which.
#!/bin/sh
for what in "$#"; do
which "$what"
done | head -1
And if you really want the exit values as well:
#!/bin/sh
for what in "$#"; do
which "$what" && exit 0
done
exit 1
The second might even be fewer resources, as it doesn't have to open a file handle and pipe through head.
You can also split your path using IFS. For example, if you wanted to wrap your loops the other way around, you could do this:
#!/bin/sh
IFS=":"
for loc in $PATH; do
for what in "$#"; do
if [ -x "$loc"/"$what" ]; then
echo "$loc"/"$what"
exit 0
fi
done
done
exit 1
Note that under normal circumstances, you might want to save the old value of $IFS, but you seem to be doing things in a stand-alone script, so the "new" value gets thrown out when the script exits.
All the above code is untested. YMMV.
Another way to get around the need to parse PATH at all is to run the builtin type command in new shell with a stripped environment (i. e. there simply are no functions or aliases to look up; cf. env -i sh -c 'type cmd 2>/dev/null).
# using `cmd` instead of $(cmd) for portability
onewhich() {
ec=0 # exit code
for cmd in "$#"; do
command -p env -i PATH="$PATH" sh -c '
export LC_ALL=C LANG=C
cmd="$1"
path="`type "$cmd" 2>/dev/null`"
if [ X"$path" = "X" ]; then
printf "%s\n" "error: command \"${cmd}\" not found in PATH" 1>&2
exit 1
else
case "$path" in
*\ /*)
path="/${path#*/}"
printf "%s\n" "$path";;
*)
printf "%s\n" "error: no disk file: $path" 1>&2
exit 1;;
esac
exit 0
fi
' _ "$cmd"
[ $? != 0 ] && ec=1
done
[ $ec != 0 ] && return 1
}
onewhich awk ls sed
onewhich builtin
onewhich if
Since which on success returns two full command paths if two commands are specified as arguments, exit 0 in the first onewhich script above aborts the program prematurely. In addition, if two commands are specified as arguments to which, the exit code of which is set to 1 even if only one command lookup failed (cf. which awk sedxyz ls; echo $?). To mimic this behaviour of the which command it is necessary to toggle on/off two variables (cnt and nomatches below).
onewhich() (
IFS=":"
nomatches=0
for cmd in "$#"; do
cnt=0
for loc in $PATH ; do
if [ $cnt = 0 ] && [ -x "$loc"/"$cmd" ]; then
echo "$loc"/"$cmd"
cnt=1
fi
done
[ $cnt = 0 ] && nomatches=1
done
[ $nomatches = 1 ] && exit 1 || exit 0 # exit 1: at least one cmd was not in PATH
)
onewhich awk ls sed
onewhich awk lsxyz sed
onewhich builtin
onewhich if
The program is very simple:
#!/bin/csh -f
foreach path ( fileA.txt fileB.txt )
wc -l $path
grep "test" $path
end
However, the output is:
fileA.txt/wc: Not a directory.
fileA.txt/grep: Not a directory.
fileB.txt/wc: Not a directory.
fileB.txt/grep: Not a directory.
So what's wrong with the code and what's the correct way of doing it?
You should never use path as a generic variable name in C-Shell since it contains the current search directories for the shell to find the command programs.
This will work much better than your code:
#!/bin/csh -f
foreach mypath ( fileA.txt fileB.txt )
wc -l $mypath
grep "test" $mypath
end
I'm trying to set up a shell script that will start a screen session (or rejoin an existing one) only if it is invoked from an interactive shell. The solution I have seen is to check if $- contains the letter "i":
#!/bin/sh -e
echo "Testing interactivity..."
echo 'Current value of $- = '"$-"
if [ `echo \$- | grep -qs i` ]; then
echo interactive;
else
echo noninteractive;
fi
However, this fails, because the script is run by a new noninteractive shell, invoked as a result of the #!/bin/sh at the top. If I source the script instead of running it, it works as desired, but that's an ugly hack. I'd rather have it work when I run it.
So how can I test for interactivity within a script?
Give this a try and see if it does what you're looking for:
#!/bin/sh
if [ $_ != $0 ]
then
echo interactive;
else
echo noninteractive;
fi
The underscore ($_) expands to the absolute pathname used to invoke the script. The zero ($0) expands to the name of the script. If they're different then the script was invoked from an interactive shell. In Bash, subsequent expansion of $_ gives the expanded argument to the previous command (it might be a good idea to save the value of $_ in another variable in order to preserve it).
From man bash:
0 Expands to the name of the shell or shell script. This is set
at shell initialization. If bash is invoked with a file of com‐
mands, $0 is set to the name of that file. If bash is started
with the -c option, then $0 is set to the first argument after
the string to be executed, if one is present. Otherwise, it is
set to the file name used to invoke bash, as given by argument
zero.
_ At shell startup, set to the absolute pathname used to invoke
the shell or shell script being executed as passed in the envi‐
ronment or argument list. Subsequently, expands to the last
argument to the previous command, after expansion. Also set to
the full pathname used to invoke each command executed and
placed in the environment exported to that command. When check‐
ing mail, this parameter holds the name of the mail file cur‐
rently being checked.
$_ may not work in every POSIX compatible sh, although it probably works in must.
$PS1 will only be set if the shell is interactive. So this should work:
if [ -z "$PS1" ]; then
echo noninteractive
else
echo interactive
fi
try tty
if tty 2>&1 |grep not ; then echo "Not a tty"; else echo "a tty"; fi
man tty :
The tty utility writes the name of the terminal attached to standard
input to standard output. The name that is written is the string
returned by ttyname(3). If the standard input is not a terminal, the
message ``not a tty'' is written.
You could try using something like...
if [[ -t 0 ]]
then
echo "Interactive...say something!"
read line
echo $line
else
echo "Not Interactive"
fi
The "-t" switch in the test field checks if the file descriptor given matches a terminal (you could also do this to stop the program if the output was going to be printed to a terminal, for example). Here it checks if the standard in of the program matches a terminal.
Simple answer: don't run those commands inside ` ` or [ ].
There is no need for either of those constructs here.
Obviously I can't be sure what you expected
[ `echo \$- | grep -qs i` ]
to be testing, but I don't think it's testing what you think it's testing.
That code will do the following:
Run echo \$- | grep -qs i inside a subshell (due to the ` `).
Capture the subshell's standard output.
Replace the original ` ` expression with a string containing that output.
Pass that string as an argument to the [ command or built-in (depending on your shell).
Produce a successful return code from [ only if that string was nonempty (assuming the string didn't look like an option to [).
Some possible problems:
The -qs options to grep should cause it to produce no output, so I'd expect [ to be testing an empty string regardless of what $- looks like.
It's also possible that the backslash is escaping the dollar sign and causing a literal 'dollar minus' (rather than the contents of a variable) to be sent to grep.
On the other hand, if you removed the [ and backticks and instead said
if echo "$-" | grep -qs i ; then
then:
your current shell would expand "$-" with the value you want to test,
echo ... | would send that to grep on its standard input,
grep would return a successful return code when that input contained the letter i,
grep would print no output, due to the -qs flags, and
the if statement would use grep's return code to decide which branch to take.
Also:
no backticks would replace any commands with the output produced when they were run, and
no [ command would try to replace the return code of grep with some return code that it had tried to reconstruct by itself from the output produced by grep.
For more on how to use the if command, see this section of the excellent BashGuide.
If you want to test the value of $- without forking an external process (e.g. grep) then you can use the following technique:
if [ "${-%i*}" != "$-" ]
then
echo Interactive shell
else
echo Not an interactive shell
fi
This deletes any match for i* from the value of $- then checks to see if this made any difference.
(The ${parameter/from/to} construct (e.g. [ "${-//[!i]/}" = "i" ] is true iff interactive) can be used in Bash scripts but is not present in Dash, which is /bin/sh on Debian and Ubuntu systems.)