How can I combine these two examples with pushd and whoami to change the directory?
I know I can change the directory like this:
#!/bin/bash
pushd /home/mike/Pictures > /dev/null
# do something in the new dir
ls
popd > /dev/null
And I know I can get the username like this:
#!/bin/bash
theuser=`whoami`
echo $theuser
You're waaay overthinking it...
cd ~/Pictures
EDIT:
Actually, no. What you really want is:
cd "$(xdg-user-dir PICTURES)"
Those backticks can be used to interpolate the output of the command they contain into another:
pushd /home/`whoami`/Pictures
Much easier than using pushd and popd, run the command in a sub-shell:
(
cd /home/$(whoami)/Pictures &&
ls
)
The sub-shell changes directory, without affecting the main process - exactly as you wanted, but rather more reliably.
It's easier just to use cd to change the directory:
#!/bin/bash
cd ~/Pictures
Among other solutions:
pushd "$HOME/Pictures"
After all, nothing obliges the home directory to bear the user name!
Bash already has the $USER variable, no need to call an external binary
pushd /home/$USER/Pictures > /dev/null
Related
I want to translate this bash-script intro a zsh-script. Hence I have no experience with this I hope I may get help here:
bash script:
SCRIPT_PATH="${BASH_SOURCE[0]}";
if([ -h "${SCRIPT_PATH}" ]) then
while([ -h "${SCRIPT_PATH}" ]) do SCRIPT_PATH=`readlink "${SCRIPT_PATH}"`; done
fi
pushd . > /dev/null
cd `dirname ${SCRIPT_PATH}` > /dev/null
SCRIPT_PATH=`pwd`;
popd > /dev/null
What I already know is that I can use
SCRIPT_PATH="$0"; to get the path were the script is located at. But then I get errors with the "readlink" statement.
Thanks for your help
Except for BASH_SOURCE I see no changes that you need to make. But what is the purpose of the script? If you want to get directory your script is located at there is ${0:A:h} (:A will resolve all symlinks, :h will truncate last path component leaving you with a directory name):
SCRIPT_PATH="${0:A:h}"
and that’s all. Note that original script has something strange going on:
if(…) and while(…) launch … in a subshell. You do not need subshell here, it is faster to do these checks using just if … and while ….
pushd . is not needed at all. While using pushd you normally replace the cd call with it:
pushd "$(dirname $SCRIPT_PATH)" >/dev/null
SCRIPT_PATH="$(pwd)"
popd >/dev/null
cd `…` will fail if … outputs something with spaces. It is possible for a directory to contain a space. In the above example I use "$(…)", "`…`" will also work.
You do not need trailing ; in variable declarations.
There is readlink -f that will resolve all symlinks thus you may consider reducing original script to SCRIPT_PATH="$(dirname $(readlink -f "${BASH_SOURCE[0]}"))" (the behavior may change as your script seems to resolve symlinks only in last component): this is bash equivalent to ${0:A:h}.
if [ -h "$SCRIPT_PATH" ] is redundant since while body with the same condition will not be executed unless script path is a symlink.
readlink $SCRIPT_PATH will return symlink relative to the directory containing $SCRIPT_PATH. Thus original script cannot possibly used to resolve symlinks in last component.
There is no ; between if(…) and then. I am surprised bash accepts this.
All of the above statements apply both to bash and zsh.
If resolving only symlinks only in last component is essential you should write it like this:
SCRIPT_PATH="$0:a"
function ResolveLastComponent()
{
pushd "$1:h" >/dev/null
local R="$(readlink "$1")"
R="$R:a"
popd >/dev/null
echo $R
}
while test -h "$SCRIPT_PATH" ; do
SCRIPT_PATH="$(ResolveLastComponent "$SCRIPT_PATH")"
done
.
To illustrate 7th statement there is the following example:
Create directory $R/bash ($R is any directory, e.g. /tmp).
Put your script there without modifications, e.g. under name $R/bash/script_path.bash. Add line echo "$SCRIPT_PATH" at the end of it and line #!/bin/bash at the start for testing.
Make it executable: chmod +x $R/bash/script_path.bash.
Create a symlink to it: cd $R/bash && ln -s script_path.bash link.
cd $R
Launch $R/bash/1. Now you will see that your script outputs $R while it should output $R/bash like it does when you launch $R/bash/script_path.bash.
I am trying to make a directory and immediately change into it with a DOSKEY. I thought this would work but it gives me the error The filename, directory name, or volume label syntax is incorrect.
DOSKEY md=mkdir $* && cd $*
Does anyone know why this is wrong and how to fix it?
I ended up finding the answer here
DOSKEY md=mkdir "$1"$tcd "$1"
I was trying to use && instead of $t
Does this work for you?
C:>doskey aaa=MKDIR "$*"$tCD "$*"
C:>doskey /macros
aaa=MKDIR "$*"$tCD "$*"
C:>aaa arf
C:>
13:33:59.15 C:\Users\pwatson\x\arf
C:>
I want to translate this bash-script intro a zsh-script. Hence I have no experience with this I hope I may get help here:
bash script:
SCRIPT_PATH="${BASH_SOURCE[0]}";
if([ -h "${SCRIPT_PATH}" ]) then
while([ -h "${SCRIPT_PATH}" ]) do SCRIPT_PATH=`readlink "${SCRIPT_PATH}"`; done
fi
pushd . > /dev/null
cd `dirname ${SCRIPT_PATH}` > /dev/null
SCRIPT_PATH=`pwd`;
popd > /dev/null
What I already know is that I can use
SCRIPT_PATH="$0"; to get the path were the script is located at. But then I get errors with the "readlink" statement.
Thanks for your help
Except for BASH_SOURCE I see no changes that you need to make. But what is the purpose of the script? If you want to get directory your script is located at there is ${0:A:h} (:A will resolve all symlinks, :h will truncate last path component leaving you with a directory name):
SCRIPT_PATH="${0:A:h}"
and that’s all. Note that original script has something strange going on:
if(…) and while(…) launch … in a subshell. You do not need subshell here, it is faster to do these checks using just if … and while ….
pushd . is not needed at all. While using pushd you normally replace the cd call with it:
pushd "$(dirname $SCRIPT_PATH)" >/dev/null
SCRIPT_PATH="$(pwd)"
popd >/dev/null
cd `…` will fail if … outputs something with spaces. It is possible for a directory to contain a space. In the above example I use "$(…)", "`…`" will also work.
You do not need trailing ; in variable declarations.
There is readlink -f that will resolve all symlinks thus you may consider reducing original script to SCRIPT_PATH="$(dirname $(readlink -f "${BASH_SOURCE[0]}"))" (the behavior may change as your script seems to resolve symlinks only in last component): this is bash equivalent to ${0:A:h}.
if [ -h "$SCRIPT_PATH" ] is redundant since while body with the same condition will not be executed unless script path is a symlink.
readlink $SCRIPT_PATH will return symlink relative to the directory containing $SCRIPT_PATH. Thus original script cannot possibly used to resolve symlinks in last component.
There is no ; between if(…) and then. I am surprised bash accepts this.
All of the above statements apply both to bash and zsh.
If resolving only symlinks only in last component is essential you should write it like this:
SCRIPT_PATH="$0:a"
function ResolveLastComponent()
{
pushd "$1:h" >/dev/null
local R="$(readlink "$1")"
R="$R:a"
popd >/dev/null
echo $R
}
while test -h "$SCRIPT_PATH" ; do
SCRIPT_PATH="$(ResolveLastComponent "$SCRIPT_PATH")"
done
.
To illustrate 7th statement there is the following example:
Create directory $R/bash ($R is any directory, e.g. /tmp).
Put your script there without modifications, e.g. under name $R/bash/script_path.bash. Add line echo "$SCRIPT_PATH" at the end of it and line #!/bin/bash at the start for testing.
Make it executable: chmod +x $R/bash/script_path.bash.
Create a symlink to it: cd $R/bash && ln -s script_path.bash link.
cd $R
Launch $R/bash/1. Now you will see that your script outputs $R while it should output $R/bash like it does when you launch $R/bash/script_path.bash.
When I change into a directory with the cd command, I lose the previous working directory, unless I remember it in my memory. Is there some handy method to go back quickly?
Demo:
$ cd ~/some_path
$ cd /another_path
$ command_to_go_back_to_some_path
You can go back to the last dir with cd -
You can also do this
$ pushd ~/some_path
$ pushd /another_path
$ popd
$ popd
As mentioned you can use cd -. The shell internally does a cd $OLDPWD.
For usage in a script, you could use the OLDPWD shell variable: it contains the previous working directory.
$ pwd
/home/username
$ cd /usr/bin
$ pwd
/usr/bin
$ cd "$OLDPWD"
$ pwd
/home/username
I prefer this over cd - in scripts because I don't have to suppress any output.
If you want to use it in a script and suppress the output, do this:
cd - > /dev/null
I'm pretty new to Bash scripting and am looking to do the following:
The script's pwd is "/a/b/c/directory_name.git/" and I'd like to cd to "../directory_name" where directory_name could be anything. Is there any easy way to do this?
I'm guessing I'd have to put the result of pwd in a variable and erase the last 4 characters.
tmpd=${PWD##*/}
cd ../${tmpd%.*}
or perhaps more simply
cd ${PWD%.*}
Test
$ myPWD="/a/b/c/directory_name.git"
$ tmpd=${myPWD##*/}
$ echo "cd ../${tmpd%.*}"
cd ../directory_name
*Note: $PWD does not include a trailing slash so the ${param##word} expansion will work just fine.
Try:
cd `pwd | sed -e s/\.git$//`
The backticks execute the command inside, and use the output of that command as a command line argument to cd.
To debug pipelines like this, it's useful to use echo:
echo `pwd | sed -e s/\.git$//`
This should work:
cd "${PWD%.*}"
Didn't expect to get so many answers so fast so I had time to come up with my own inelegant solution:
#!/bin/bash
PWD=`pwd`
LEN=${#PWD}
END_POSITION=LEN-4
WORKING_COPY=${PWD:0:END_POSITION}
echo $WORKING_COPY
cd $WORKING_COPY
There's probably one above that's much more elegant :)
That's what basename is for:
cd ../$(basename "$(pwd)" .git)