Passing bash argument as string - bash

i have a little and probably very stupid problem..
I'm trying to make an alias for tar and gzip which uses the file name (given as an argument), but it is not converting as expected to the filename in the output.
My alias is:
alias targz='tar -cvzf $1.tar.gz $1'
It works, but the argument stored in $1 is not working when setting the filename, it zips it in a file called ".tar.gz".
I tried just echoing '$1.tar.gz' and the output is '.tar.gz', so, i think it should be something very stupid in the format.
Any help is welcome,

Aliases don't have positional parameters. They're basically macros (an alias gets replaced with the text of the alias when executed).
You could use a function:
targz() {
tar -cvzf "$1".tar.gz "$1"
}
or a script
#!/bin/bash
tar -cvzf "$1".tar.gz "$1"
Personally, I've been using something like the following script to achieve a similar goal (comments added for your convenience):
#!/bin/bash
#support multiple args
for arg in "$#"
do
#strip ending slash if present (tab-completion adds them)
arg=${arg%/}
#compress with pigz (faster on multicore systems)
tar c "$arg" | pigz - > "$arg".tgz
done
In case you want my complete version, I also remove the argument directory if the tarring and compression succeed (similar to what gzip does for individual files)
#!/bin/bash
set -o pipefail
for arg in "$#"
do
arg=${arg%/}
tar c "$arg" | pigz - > "$arg".tgz && rm -rf "$arg"
done
Update:
Credits to #mklement0 for the more succinct and more efficient stripping of ending slashes.

Use an alias to a function for it, something like:
alias targz='function targz_() { tar -cvzf "$1.tar.gz" "$1"; return 0; }; targz_ '

Try to make a script to do that, like this.
echo """
#!/bin/bash if [ -z $1 ]; then
echo "Variable is Null"
else
tar -cvzf $1.tar.gz $1
fi
""" > /usr/local/bin/targz
chmod +x /usr/local/bin/targz

Related

Understanding a docker entrypoint script

The script is located here: https://github.com/docker-library/ghost/blob/master/docker-entrypoint.sh
#!/bin/bash
set -e
if [[ "$*" == npm*start* ]]; then
baseDir="$GHOST_SOURCE/content"
for dir in "$baseDir"/*/ "$baseDir"/themes/*/; do
targetDir="$GHOST_CONTENT/${dir#$baseDir/}"
mkdir -p "$targetDir"
if [ -z "$(ls -A "$targetDir")" ]; then
tar -c --one-file-system -C "$dir" . | tar xC "$targetDir"
fi
done
if [ ! -e "$GHOST_CONTENT/config.js" ]; then
sed -r '
s/127\.0\.0\.1/0.0.0.0/g;
s!path.join\(__dirname, (.)/content!path.join(process.env.GHOST_CONTENT, \1!g;
' "$GHOST_SOURCE/config.example.js" > "$GHOST_CONTENT/config.js"
fi
ln -sf "$GHOST_CONTENT/config.js" "$GHOST_SOURCE/config.js"
chown -R user "$GHOST_CONTENT"
set -- gosu user "$#"
fi
exec "$#"
From what I know, it says that if you use some variation of npm start to move some files around from $GHOST_SOURCE to $GHOST_CONTENT, do something to the config.js file, link the config file, set ownership of the content files, and then execute npm start as the user user. Otherwise, it just runs your commands normally.
The specifics are what are hard for me to understand because there are a lot of things from bash that I've never seen before. So I have a lot of questions.
for dir in "$baseDir"/*/ "$baseDir"/themes/*/; do
In the above, why do they specify both /*/ and /themes/*/? Shouldn't /*/ contain themes? Is * not a wildcard for some reason?
targetDir="$GHOST_CONTENT/${dir#$baseDir/}"
In the above, what is the point of # in the variable expansion?
tar -c --one-file-system -C "$dir" . | tar xC "$targetDir"
In the above, does this somehow save time? Why not use something like rsync? I understand the point of -C, but why -c and --one-file-system?
sed -r '
s/127\.0\.0\.1/0.0.0.0/g;
s!path.join\(__dirname, (.)/content!path.join(process.env.GHOST_CONTENT, \1!g;
' "$GHOST_SOURCE/config.example.js" > "$GHOST_CONTENT/config.js"
What does this sed command do? I know it's a replacement, but why the "$GHOST_SOURCE/config.example.js" > "$GHOST_CONTENT/config.js" as the end?
ln -sf "$GHOST_CONTENT/config.js" "$GHOST_SOURCE/config.js"
In the above, what is the point of this symlink? Why try to link them to each other if both files already exist?
set -- gosu user "$#"
In the above what does calling set with no args do?
I hope that's not too much. I felt making a separate question for each of these would be too much especially since it's all related to each other.
for dir in "$baseDir"/*/ "$baseDir"/themes/*/; do
In the above, why do they specify both /*/ and /themes/*/? Shouldn't
/*/ contain themes? Is * not a wildcard for some reason?
themes/ is in the first match, but themes/*/ is not, so you need the second entry to include the contents of themes.
targetDir="$GHOST_CONTENT/${dir#$baseDir/}"
In the above, what is the point of # in the variable expansion?
It removes the $baseDir prefix from $dir. So for example:
bash$ dir=/home/bmitch/data/docker
bash$ echo $dir
/home/bmitch/data/docker
bash$ echo ${dir#/home/bmitch}
/data/docker
tar -c --one-file-system -C "$dir" . | tar xC "$targetDir"
In the above, does this somehow save time? Why not use something like
rsync? I understand the point of -C, but why -c and --one-file-system?
rsync may not be installed on every machine by default, tar is fairly universal. The -c is to create, vs extract, and --one-file-system avoids tar continuing to an outside mount point (nfs, symlink to root, etc).
sed -r '
s/127\.0\.0\.1/0.0.0.0/g;
s!path.join\(__dirname, (.)/content!path.join(process.env.GHOST_CONTENT, \1!g;
' "$GHOST_SOURCE/config.example.js" > "$GHOST_CONTENT/config.js"
What does this sed command do? I know it's a replacement, but why the
"$GHOST_SOURCE/config.example.js" > "$GHOST_CONTENT/config.js" as the
end?
config.example.js is the input (last arg to the sed), config.js is the output (after the >). So it takes the config.example.js, change the ip address from 127.0.0.1 to 0.0.0.0, effectively listening on all interfaces/ip's instead of just internally on the loopback. The second half of the sed is changing the path.join arguments from __dirname to process.env.GHOST_CONTENT.
ln -sf "$GHOST_CONTENT/config.js" "$GHOST_SOURCE/config.js"
In the above, what is the point of this symlink? Why try to link them
to each other if both files already exist?
The $GHOST_SOURCE/config.js is replaced (-f) with a link to $GHOST_CONTENT/config.js. Symbolic links give a file name reference to another actual file, so there will be two names, but one copy of the data, which means you will only have a single configuration in this situation.
set -- gosu user "$#"
In the above what does calling set with no args do?
This changes the values of $1, $2, ... $n to be $1=gosu, $2=user, $3=the old $1, $4=the old $2..., essentially adding the gosu and user to the beginning of the passed parameters to the script. The -- makes sure that set doesn't interpret any values from $# as a flag for itself.

Shell script to browse one or more directories passed as parameters

I made this script that should receive one or more parameter, and those parameter are all directories, and it has to browse those directories (one by one) and do some operations.
The operations work fine if the parameter is 1 (only one directory),
How should I modify my script to make it works if more than 1 parameter is passed
Example if I want it to do the same operations in 2 or 3 directories at the same time?
Thanks
#!/bin/sh
cd $1
for file in ./* # */
do
if [[ -d $file ]]
then
ext=dir
else
ext="${file##*.}"
fi
mv "${file}" "${file}.$ext"
done
First, if you are using bash use bash shebang (#! /bin/bash).
Then use
#! /bin/bash
for d in "$#"
do
echo "Do something with $d"
done
to iterate over the command line arguments (dirs in your case)
#!/bin/sh
for dir in "$#"; do
for file in "$dir"/*; do
echo "Doing something with '$file'"
done
done

Shell Script and spaces in path

I have larger shell script which handles different things.
It will get it's own location by the following...
BASEDIR=`dirname $0`/..
BASEDIR=`(cd "$BASEDIR"; pwd)`
then BASEDIR will be used create other variables like
REPO="$BASEDIR"/repo
But the problem is that this shell script does not work if the path contains spaces where it is currently executed.
So the question is: Does exist a good solution to solve that problem ?
Be sure to double-quote anything that may contain spaces:
BASEDIR="`dirname $0`"
BASEDIR="`(cd \"$BASEDIR\"; pwd)`"
The answer is "Quotes everywhere."
If the path you pass in has a space in it then dirname $0 will fail.
$ cat quote-test.sh
#!/bin/sh
test_dirname_noquote () {
printf 'no quotes: '
dirname $1
}
test_dirname_quote () {
printf 'quotes: '
dirname "$1"
}
test_dirname_noquote '/path/to/file with spaces/in.it'
test_dirname_quote '/path/to/file with spaces/in.it'
$ sh quote-test.sh
no quotes: usage: dirname string
quotes: /path/to/file with spaces
Also, try this fun example
#!/bin/sh
mkdir -p /tmp/foo/bar/baz
cd /tmp/foo
ln -s bar quux
cd quux
cat >>find-me.sh<<"."
#!/bin/sh
self_dir="$(dirname $0)"
base_dir="$( (cd "$self_dir/.." ; pwd -P) )"
repo="$base_dir/repo"
printf 'self: %s\n' "$self_dir"
printf 'base: %s\n' "$base_dir"
printf 'repo: %s\n' "$repo"
.
sh find-me.sh
rm -rf /tmp/foo
Result when you run it:
$ sh example.sh
self: .
base: /tmp/foo
repo: /tmp/foo/repo
Quote your full variable like this:
REPO="$BASEDIR/repo"
There is no reliable and/or portable way to do this correctly.
See How do I determine the location of my script? as to why
The best answer is the following, which is still OS dependent
BASEDIR=$(readlink -f $0)
Then you can do things like REPO="$BASEDIR"/repo , just be sure to quote your variables as you did.
Works perfectly fine for me. How are you using REPO? What specifically "doesn't work" for you?
I tested
#!/bin/sh
BASEDIR=`dirname $0`/..
BASEDIR=`(cd "$BASEDIR"; pwd)`
REPO="$BASEDIR"/repo
echo $REPO
in a ".../a b/c d" directory. It outputs ".../a b/repo", as expected.
Please give the specific error that you are receiving... A "doesn't work" bug report is the least useful bug report, and every programmer absolutely hates it.
Using spaces in directory names in unix is always an issue so if they can be avoided by using underscores, this prevents lots of strange scripting behaviour.
I'm unclear why you are setting BASEDIR to be the parent directory of the directory containing the current script (..) and then resetting it after changing into that directory
The path to the directory should still work if it has ..
e.g. /home/trevor/data/../repo
BASEDIR=`dirname $0`/..
I think if you echo out $REPO it should have the path correctly assigned because you used quotes when assigning it but if you then try to use $REPO somewhere else in the script, you will need to use double quotes around that too.
e.g.
#!/bin/ksh
BASEDIR=`dirname $0`/..
$REPO="$BASEDIR"/repo
if [ ! -d ["$REPO"]
then
echo "$REPO does not exist!"
fi
Use speech marks as below:
BASEDIR=`dirname "${0}"`/..

Shell scripting debug help - Iterating through files in a directory

#!/bin/sh
files = 'ls /myDir/myDir2/myDir3/'
for file in $files do
echo $file
java myProg $file /another/directory/
done
What i'm trying to do is iterate through every file name under /myDir/myDir2/myDir3/, then use that file name as the first argument in calling a java program (second argument is "/another/directory")
When I run this script: . myScript.sh
I get this error:
-bash: files: command not found
What did I do wrong in my script? Thanks!
Per Neeaj's answer, strip off the whitespace from files =.
Better yet, use:
#!/bin/sh -f
dir=/myDir/MyDir2/MyDir3
for path in $dir/*; do
file=$(basename $path)
echo "$file"
java myProg "$file" arg2 arg3
done
Bash is perfectly capable of expanding the * wildcard itself, without spawning a copy of ls to do the job for it!
EDIT: changed to call basename rather than echo to meet OP's (previously unstated) requirement that the path echoed be relative and not absolute. If the cwd doesn't matter, then even better I'd go for:
#!/bin/sh -f
cd /myDir/MyDir2/MyDir3
for file in *; do
echo "$file"
java myProg "$file" arg2 arg3
done
and avoid the calls to basename altogether.
strip off the whitespace in and after files = as files=RHS of assignment
Remove the space surrounding the '=' : change
files = 'ls /myDir/myDir2/myDir3/'
into:
files='ls /myDir/myDir2/myDir3/'
and move the 'do' statement to its own line:
for file in $files
do
....
quote your variables and no need to use ls.
#!/bin/sh
for file in /myDir/myDir2/*
do
java myProg "$file" /another/directory/
done

Can I specify redirects and pipes in variables?

I have a bash script that creates a Subversion patch file for the current directory. I want to modify it to zip the produced file, if -z is given as an argument to the script.
Here's the relevant part:
zipped=''
zipcommand='>'
if [ "$1" = "-z" ]
then
zipped='zipped '
filename="${filename}.zip"
zipcommand='| zip >'
fi
echo "Creating ${zipped}patch file $filename..."
svn diff $zipcommand $filename
This doesn't work because it passes the | or > contained in $zipcommand as an argument to svn.
I can easily work around this, but the question is whether it's ever possible to use these kinds of operators when they're contained in variables.
Thanks!
I would do something like this (use bash -c or eval):
zipped=''
zipcommand='>'
if [ "$1" = "-z" ]
then
zipped='zipped '
filename="${filename}.zip"
zipcommand='| zip -#'
fi
echo "Creating ${zipped}patch file $filename..."
eval "svn diff $zipcommand $filename"
# this also works:
# bash -c "svn diff $zipcommand $filename"
This appears to work, but my version of zip (Mac OS X) required that i change the line:
zipcommand='| zip -#'
to
zipcommand='| zip - - >'
Edit: incorporated #DanielBungert's suggestion to use eval
eval is what you are looking for.
# eval 'printf "foo\nbar" | grep bar'
bar
Be careful with quote characters on that.
Or you should try zsh shell whic allows to define global aliases, e.g.:
alias -g L='| less'
alias -g S='| sort'
alias -g U='| uniq -c'
Then use this command (which is somewhat cryptic for the ones who took a look from behind ;-) )
./somecommand.sh S U L
HTH
Open a new file handle on either a process substitution to handle the compression or on the named file. Then redirect the output of svn diff to that file handle.
if [ "$1" = "-z" ]; then
zipped='zipped '
filename=$filename.zip
exec 3> >(zip > "$filename")
else
exec 3> "$filename"
fi
echo "Creating ${zipped}patch file $filename"
svn diff >&3

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