I'm currently having an assignment to write a bash script that can perform backup log (syslog, dmesg and message) files to a new directory. I wrote my script like this:
cd /var/log
sudo cp syslog Assignment
The file "Assignment" is in my home directory. When I used the "ls" command in my Assignment folder, I don't find a copy of syslog in there. Can someone tell me where did I go wrong? Thanks in advance.
I think you mean Assignment folder, not Assignment file. Anyways if you cd to /var/log, then when you do a cp in /var/log it will think Assignment is local to /var/log. If you do an ls in /var/log now you will see a copy of syslog called Assignment in /var/log. To get syslog copied to the assignment folder in your home directory you need to specify the absolute path not the relative path. Use the tilde, ~, to specify the home directory. So your script should say
cd /var/log
sudo cp syslog ~/Assignment/
You can try this:
#!/bin/sh
if ! [ $1 ] ; then
echo "Usage:";
echo $0 "<directory_where_to_save_logs>";
return;
fi
if [ ! -d "$1" ]; then
echo "Creating directory $1";
mkdir $1;
fi
cp /var/log/syslog* $1
cp /var/log/dmesg* $1
Thanks
Related
I have a directory mnt/d/LIVI.
Inside the directory, LIVI, I have sub-directories:
mnt/d/LIVI/ak
mnt/d/LIVI/ag
mnt/d/LIVI/few
mnt/d/LIVI/ww4
mnt/d/LIVI/ks5
I wanted to copy a file named tt.txt from mnt/d/LIVI/ak/tt.txt and paste to all the sub directories of LIVI, using Ubuntu terminal. How do i do it using a shell script file?
I tried the following one, but it didn't work.
I created a text file named mnt/d/LIVI/FOLDERS.txt, This listed all the sub directories names.
And saved a script file in mnt/d/LIVI directory. The following is the script
#!/bin/sh
# -*- coding: utf-8-unix -*-
ROOTDIR=$(dirname $0 | xargs readlink -f)
for SIMDIR in cat FOLDERS.txt | xargs readlink -f ; do
cp mnt/d/LIVI/ak/tt.txt $SIMDIR
done
#cd ..
date
You may try this bash script
#!/bin/bash
cd "${0%/*}" || exit
for dir in */; do
if [[ $dir != 'ak/' ]]; then
cp ak/tt.txt "$dir"
fi
done
The script must reside under the diectory mnt/d/LIVI
Don't read lines with for.
(If you really wanted to, the syntax for that would look like
for dir in $(cat FOLDERS.txt); do
...
but really, don't. The link above explains why in more detail.)
I don't see why you want to run readlink on the directories at all?
cd "$(dirname "$0")"
while read -r dir; do
cp ak/tt.txt "$dir"
done <FOLDERS.txt
Note also Correct Bash and shell script variable capitalization
I have an environment variable containing the name of a directory. I am trying to redirect output from an echo command to a text file in a different directory.
For example
DIR="NewDirectory"
mkdir $DIR
echo "Testing" >> "$DIR\file.txt"
Results in a file named NewDirectory\file.txt in the working directory of the script...what exactly am I missing here? The directory is created without issue, so I am not sure what is going on here.
You have to change \ into /:
DIR="NewDirectory"
mkdir -p $DIR
echo "Testing" >> "$DIR/file.txt"
Changed mkdir -p as suggested by #Jord, because -p means: no error if existing, make parent directories as needed
In linux (or unix for that matter), the directory separator is a slash (/), not a backslash (\):
DIR="NewDirectory"
mkdir $DIR
echo "Testing" >> "$DIR/file.txt"
Your line
echo "Testing" >> "$DIR\file.txt"
should read
echo "Testing" >> "$DIR/file.txt"
as / is the separator in paths in Linux.
I have written a Bash script that takes an input file as an argument and reads it.
This file contains some paths (relative to its location) to other files.
I would like the script to go to the folder containing the input file, to execute further commands.
In Linux, how do I get the folder (and just the folder) from an input file?
To get the full path use:
readlink -f relative/path/to/file
To get the directory of a file:
dirname relative/path/to/file
You can also combine the two:
dirname $(readlink -f relative/path/to/file)
If readlink -f is not available on your system you can use this*:
function myreadlink() {
(
cd "$(dirname $1)" # or cd "${1%/*}"
echo "$PWD/$(basename $1)" # or echo "$PWD/${1##*/}"
)
}
Note that if you only need to move to a directory of a file specified as a relative path, you don't need to know the absolute path, a relative path is perfectly legal, so just use:
cd $(dirname relative/path/to/file)
if you wish to go back (while the script is running) to the original path, use pushd instead of cd, and popd when you are done.
* While myreadlink above is good enough in the context of this question, it has some limitation relative to the readlink tool suggested above. For example it doesn't correctly follow a link to a file with different basename.
Take a look at realpath which is available on GNU/Linux, FreeBSD and NetBSD, but not OpenBSD 6.8. I use something like:
CONTAININGDIR=$(realpath ${FILEPATH%/*})
to do what it sounds like you're trying to do.
This will work for both file and folder:
absPath(){
if [[ -d "$1" ]]; then
cd "$1"
echo "$(pwd -P)"
else
cd "$(dirname "$1")"
echo "$(pwd -P)/$(basename "$1")"
fi
}
$cat abs.sh
#!/bin/bash
echo "$(cd "$(dirname "$1")"; pwd -P)"
Some explanations:
This script get relative path as argument "$1"
Then we get dirname part of that path (you can pass either dir or file to this script): dirname "$1"
Then we cd "$(dirname "$1"); into this relative dir
pwd -P and get absolute path. The -P option will avoid symlinks
As final step we echo it
Then run your script:
abs.sh your_file.txt
Try our new Bash library product realpath-lib over at GitHub that we have given to the community for free and unencumbered use. It's clean, simple and well documented so it's great to learn from. You can do:
get_realpath <absolute|relative|symlink|local file path>
This function is the core of the library:
if [[ -f "$1" ]]
then
# file *must* exist
if cd "$(echo "${1%/*}")" &>/dev/null
then
# file *may* not be local
# exception is ./file.ext
# try 'cd .; cd -;' *works!*
local tmppwd="$PWD"
cd - &>/dev/null
else
# file *must* be local
local tmppwd="$PWD"
fi
else
# file *cannot* exist
return 1 # failure
fi
# reassemble realpath
echo "$tmppwd"/"${1##*/}"
return 0 # success
}
It's Bash 4+, does not require any dependencies and also provides get_dirname, get_filename, get_stemname and validate_path.
Problem with the above answer comes with files input with "./" like "./my-file.txt"
Workaround (of many):
myfile="./somefile.txt"
FOLDER="$(dirname $(readlink -f "${ARG}"))"
echo ${FOLDER}
I have been using readlink -f works on linux
so
FULL_PATH=$(readlink -f filename)
DIR=$(dirname $FULL_PATH)
PWD=$(pwd)
cd $DIR
#<do more work>
cd $PWD
I have an array variable tht contains all directories in a folder.
I need to cd to each directory in the $array. bt when it reach to a non accessible directory , program halts . how can I avoid this so that my loop simply go to the next directory. code is
foreach dir ($array)
cd $dir
echo "directory is $dir"
cd - end
please help !!
Just test that the cd worked.
( if cd $dir 2> /dev/null; then
echo in directory $dir
# Do other things
fi )
Also, note the parentheses. These cause the entire clause to run in a subshell, so there's no need to cd back to the original location.
If iam not mistaken you can use something like
if [ -r ${dir} ]
then
echo "Have read access!"
fi
You can use -w for testing write access and -x for testing for the exceution bit.
How to create folders like: wdw/1/11, wdw/2/22, ... wdw/6/66, ..., wdw/9/99, and file using directory name in the deepest directory like directoryname_file.txt
In bash:
mkdir wdw # Creates the top dir.
mkdir {1..9} # Creates the subdirs using brace expansion.
for dir in {1..9} ; do
mkdir $dir/$dir$dir # Creates the subsubdirs.
touch $dir/$dir$dir/$dirdir"_file".txt # Creates the file.
done
In Bash, you can use the mkdir command:
your_dir="wdw/1/11"
if [ ! -d $your_dir ]; then
mkdir $your_dir
fi
The IF clause is to check if the directory already exists.
You can loop to change the value of "your_dir" with /2/22, 6/66, etc...
You'll have use the -p flag with mkdir to create nested directories, for example:
dir_name="wdw/1/11"
mkdir -p $dir_name
Then use touch or echo to create the files:
touch $dir_name/directoryname_file.txt
or
echo "some text" > $dir_name/directoryname_file.txt