Escaping character from Windows to WSL - bash

I am trying to send the following line :
trap 'test -n "$SSH_AUTH_SOCK" && eval `/usr/bin/ssh-agent -k`' 0
to a file from Windows to WSL.
Here is what I've got so far :
bash -c "echo -e 'trap test -n \"\$SSH_AUTH_SOCK\" && eval \`/usr/bin/ssh-agent -k\` 0' >> $HOME/test"
I can't find a way to quote the trap argument. Thanks in advence for your help.

A colleague of mine found a solution : use a fonction
bash -c "echo -e 'onexit() { test -n \"\$SSH_AUTH_SOCK\" && eval \`/usr/bin/ssh-agent -k\`; }' > $HOME/testA"
bash -c "echo -e trap onexit 0 >> $HOME/testA"

Related

shell script to execute a nohup task inside a docker

referred
Tried the following, to execute the below nohup commands inside a container,
nohup sh $KAFKA_HOME/bin/connect-standalone.sh $KAFKA_HOME/config/connect-standalone-mongo.properties $KAFKA_HOME/config/connect-mongo-sink.properties &
nohup /bin/bash $KAFKA_HOME/bin/connect-standalone.sh $KAFKA_HOME/config/connect-standalone-mongo.properties $KAFKA_HOME/config/connect-mongo-sink.properties &
And tried the below as well,
declare -a parameters=( "/opt/kafka/config/connect-standalone-mongo.properties" "/opt/kafka/config/connect-mongo-sink.properties")
for parameter in "${parameters[#]}"
do
echo "$1" > "/tmp/test02.txt"
nohup /bin/sh $KAFKA_HOME/bin/connect-standalone.sh -p $parameter 1> ${parameter}_nohup.out 2> ${parameter}_nohup.err &
#message received
echo "$1" > "/tmp/test03.txt"
done[referred the following link as well][1]
when I tried the below I am getting and empty out file,
$(nohup .$KAFKA_HOME/bin/connect-standalone.sh $KAFKA_HOME/config/connect-standalone-mongo.properties $KAFKA_HOME/config/connect-mongo-sink.properties > out.txt &)
The below way of scripting works for me!!!!!!!!!
ex=' /opt/kafka/bin/connect-standalone.sh /opt/kafka/config/connect-standalone-mongo.properties /opt/kafka/config/connect-mongo-sink.properties > /opt/kafka/kafka-mongo-info.out 2> /opt/kafka/kafka-mongo-error.err &'
while true
do
# nohup $ex 1> nohup_kms.out 2> nohup_kms.err | tee -a /var/log/my_uber_script.log
# nohup $ex 1> nohup_kms.out 2> nohup_kms.err
done
you can try any one inside the loop

How to change argv[0] value in shell / bash script?

The set command can be used to change values of the positional arguments $1 $2 ...
But, is there any way to change $0 ?
In Bash greater than or equal to 5 you can change $0 like this:
$ cat bar.sh
#!/bin/bash
echo $0
BASH_ARGV0=lol
echo $0
$ ./bar.sh
./bar.sh
lol
ZSH even supports assigning directly to 0:
$ cat foo.zsh
#!/bin/zsh
echo $0
0=lol
echo $0
$ ./foo.zsh
./foo.zsh
lol
Here is another method. It is implemented through direct commands execution which is somewhat better than sourcing (the dot command). But, this method works only for shell interpreter, not bash, since sh supports -s -c options passed together:
#! /bin/sh
# try executing this script with several arguments to see the effect
test ".$INNERCALL" = .YES || {
export INNERCALL=YES
cat "$0" | /bin/sh -s -c : argv0new "$#"
exit $?
}
printf "argv[0]=$0\n"
i=1 ; for arg in "$#" ; do printf "argv[$i]=$arg\n" ; i=`expr $i + 1` ; done
The expected output of the both examples in case ./the_example.sh 1 2 3 should be:
argv[0]=argv0new
argv[1]=1
argv[2]=2
argv[3]=3
#! /bin/sh
# try executing this script with several arguments to see the effect
test ".$INNERCALL" = .YES || {
export INNERCALL=YES
# this method works both for shell and bash interpreters
sh -c ". '$0'" argv0new "$#"
exit $?
}
printf "argv[0]=$0\n"
i=1 ; for arg in "$#" ; do printf "argv[$i]=$arg\n" ; i=`expr $i + 1` ; done

Get command used to start a script

How to get the command previously used to start a shell script?
for example:
nohup /script_name.sh &
Inside the script itself, how to check if "nohup" has been used?
Thanks.
You want to use the $_ parameter in your script.
Example: shell.sh
#!/bin/bash
echo $_;
user#server [~]# sh shell.sh
/usr/bin/sh
user#server [~]#
Additionally:
If you want to get rid of that full path - /usr/bin/sh - utilize basename command.
#!/bin/bash
echo `basename $_`;
user#server [~]# sh shell.sh
sh
user#server [~]#
well that depends on the script in question.There're many ways to execute a script like:
./<scriptname> #chmod 700 <scriptname> should be done before executing this script
bash <scriptname> # provided bash is used for executing the script.
or if you just want to get the name of script2 in script1, then use sed or awk for parsing the script1 with regular expression => /script2/.
Try this:
cat <script1> | awk '{ if( $0 ~ /^[^#].* \/scriptname.sh/ ){ print $1}}'
#codebaus thanks, doing something like this works but using strace definitely not.
#!/bin/bash
# echo $_
# echo $0
if grep "sh" $_ >/dev/null ; then
exit 1
fi ;
echo "string" ;
I believe you want to run this?:
#!/bin/bash
# echo $_
# echo $0
if grep "sh" $_ 2> /dev/null ; then
exit 1
fi ;
echo "string";
user#server [~]# sh shell.sh
Binary file /usr/bin/sh matches
user#server [~]#
Not sure what you are trying to accomplish in the end game. But $_ should give you what you need based on your initial question.
Additionally:
As I did not answer your strace comment, apologies. Based on the previous code above.
strace sh shell.sh
wait4(-1, Binary file /usr/bin/strace matches
[{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 874
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
--- SIGCHLD (Child exited) # 0 (0) ---

How can I get the PID of a subshell in bash3.x?

Is it possible to get $BASHPID value in bash3.x?
Actually, I cannot find any description about it in bash3.x man, but it's available in bash4.x.
You can try: bash -c 'echo $PPID'. This works for me on bash 4.1:
$ echo $$
8792
$ ( echo $BASHPID; echo $(bash -c 'echo $PPID') )
12987
12987

How to trick an application into thinking its stdout is a terminal, not a pipe

I'm trying to do the opposite of "Detect if stdin is a terminal or pipe?".
I'm running an application that's changing its output format because it detects a pipe on STDOUT, and I want it to think that it's an interactive terminal so that I get the same output when redirecting.
I was thinking that wrapping it in an expect script or using a proc_open() in PHP would do it, but it doesn't.
Any ideas out there?
Aha!
The script command does what we want...
script --return --quiet -c "[executable string]" /dev/null
Does the trick!
Usage:
script [options] [file]
Make a typescript of a terminal session.
Options:
-a, --append append the output
-c, --command <command> run command rather than interactive shell
-e, --return return exit code of the child process
-f, --flush run flush after each write
--force use output file even when it is a link
-q, --quiet be quiet
-t[<file>], --timing[=<file>] output timing data to stderr or to FILE
-h, --help display this help
-V, --version display version
Based on Chris' solution, I came up with the following little helper function:
faketty() {
script -qfc "$(printf "%q " "$#")" /dev/null
}
The quirky looking printf is necessary to correctly expand the script's arguments in $# while protecting possibly quoted parts of the command (see example below).
Usage:
faketty <command> <args>
Example:
$ python -c "import sys; print(sys.stdout.isatty())"
True
$ python -c "import sys; print(sys.stdout.isatty())" | cat
False
$ faketty python -c "import sys; print(sys.stdout.isatty())" | cat
True
The unbuffer script that comes with Expect should handle this ok. If not, the application may be looking at something other than what its output is connected to, eg. what the TERM environment variable is set to.
Referring previous answer, on Mac OS X, "script" can be used like below...
script -q /dev/null commands...
But, because it may replace "\n" with "\r\n" on the stdout, you may also need script like this:
script -q /dev/null commands... | perl -pe 's/\r\n/\n/g'
If there are some pipe between these commands, you need to flush stdout. for example:
script -q /dev/null commands... | ruby -ne 'print "....\n";STDOUT.flush' | perl -pe 's/\r\n/\n/g'
I don't know if it's doable from PHP, but if you really need the child process to see a TTY, you can create a PTY.
In C:
#include <stdio.h>
#include <stdlib.h>
#include <sysexits.h>
#include <unistd.h>
#include <pty.h>
int main(int argc, char **argv) {
int master;
struct winsize win = {
.ws_col = 80, .ws_row = 24,
.ws_xpixel = 480, .ws_ypixel = 192,
};
pid_t child;
if (argc < 2) {
printf("Usage: %s cmd [args...]\n", argv[0]);
exit(EX_USAGE);
}
child = forkpty(&master, NULL, NULL, &win);
if (child == -1) {
perror("forkpty failed");
exit(EX_OSERR);
}
if (child == 0) {
execvp(argv[1], argv + 1);
perror("exec failed");
exit(EX_OSERR);
}
/* now the child is attached to a real pseudo-TTY instead of a pipe,
* while the parent can use "master" much like a normal pipe */
}
I was actually under the impression that expect itself does creates a PTY, though.
Updating #A-Ron's answer to
a) work on both Linux & MacOs
b) propagate status code indirectly (since MacOs script does not support it)
faketty () {
# Create a temporary file for storing the status code
tmp=$(mktemp)
# Ensure it worked or fail with status 99
[ "$tmp" ] || return 99
# Produce a script that runs the command provided to faketty as
# arguments and stores the status code in the temporary file
cmd="$(printf '%q ' "$#")"'; echo $? > '$tmp
# Run the script through /bin/sh with fake tty
if [ "$(uname)" = "Darwin" ]; then
# MacOS
script -Fq /dev/null /bin/sh -c "$cmd"
else
script -qfc "/bin/sh -c $(printf "%q " "$cmd")" /dev/null
fi
# Ensure that the status code was written to the temporary file or
# fail with status 99
[ -s $tmp ] || return 99
# Collect the status code from the temporary file
err=$(cat $tmp)
# Remove the temporary file
rm -f $tmp
# Return the status code
return $err
}
Examples:
$ faketty false ; echo $?
1
$ faketty echo '$HOME' ; echo $?
$HOME
0
embedded_example () {
faketty perl -e 'sleep(5); print "Hello world\n"; exit(3);' > LOGFILE 2>&1 </dev/null &
pid=$!
# do something else
echo 0..
sleep 2
echo 2..
echo wait
wait $pid
status=$?
cat LOGFILE
echo Exit status: $status
}
$ embedded_example
0..
2..
wait
Hello world
Exit status: 3
Too new to comment on the specific answer, but I thought I'd followup on the faketty function posted by ingomueller-net above since it recently helped me out.
I found that this was creating a typescript file that I didn't want/need so I added /dev/null as the script target file:
function faketty { script -qfc "$(printf "%q " "$#")" /dev/null ; }
There's also a pty program included in the sample code of the book "Advanced Programming in the UNIX Environment, Second Edition"!
Here's how to compile pty on Mac OS X:
man 4 pty # pty -- pseudo terminal driver
open http://en.wikipedia.org/wiki/Pseudo_terminal
# Advanced Programming in the UNIX Environment, Second Edition
open http://www.apuebook.com
cd ~/Desktop
curl -L -O http://www.apuebook.com/src.tar.gz
tar -xzf src.tar.gz
cd apue.2e
wkdir="${HOME}/Desktop/apue.2e"
sed -E -i "" "s|^WKDIR=.*|WKDIR=${wkdir}|" ~/Desktop/apue.2e/Make.defines.macos
echo '#undef _POSIX_C_SOURCE' >> ~/Desktop/apue.2e/include/apue.h
str='#include <sys/select.h>'
printf '%s\n' H 1i "$str" . wq | ed -s calld/loop.c
str='
#undef _POSIX_C_SOURCE
#include <sys/types.h>
'
printf '%s\n' H 1i "$str" . wq | ed -s file/devrdev.c
str='
#include <sys/signal.h>
#include <sys/ioctl.h>
'
printf '%s\n' H 1i "$str" . wq | ed -s termios/winch.c
make
~/Desktop/apue.2e/pty/pty ls -ld *
I was trying to get colors when running shellcheck <file> | less on Linux, so I tried the above answers, but they produce this bizarre effect where text is horizontally offset from where it should be:
In ./all/update.sh line 6:
for repo in $(cat repos); do
^-- SC2013: To read lines rather than words, pipe/redirect to a 'while read' loop.
(For those unfamiliar with shellcheck, the line with the warning is supposed to line up with the where the problem is.)
In order to the answers above to work with shellcheck, I tried one of the options from the comments:
faketty() {
0</dev/null script -qfc "$(printf "%q " "$#")" /dev/null
}
This works. I also added --return and used long options, to make this command a little less inscrutable:
faketty() {
0</dev/null script --quiet --flush --return --command "$(printf "%q " "$#")" /dev/null
}
Works in Bash and Zsh.

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