So I have googled this and thought I found the answers, but it still doesnt work for me.
The program computes the average and median of rows and columns in a file of numbers...
Using the file name works:
./stats -columns test_file
Using cat does not work
cat test_file | ./stats -columns
I am not sure why it doesnt work
#file name was given
if [[ $# -eq 2 ]]
then
fileName=$2
#file name was not given
elif [[ $# -eq 1 ]]
then
#file name comes from the user
fileName=/dev/stdin
#incorrect number of arguments
else
echo "Usage: stats {-rows|-cols} [file]" 1>&2
exit 1
fi
A very simple program that accepts piped input:
#!/bin/sh
stdin(){
while IFS= read -r i
do printf "%s" "$i"
done
}
stdin
Test is as follows:
echo "This is piped output" | stdin
To put that into a script / utility similar to the one in the question you might do this:
#!/bin/sh
stdin(){
while IFS= read -r i
do printf "%s" "$i"
done
}
rowbool=0
colbool=0
for i in $#
do case "$i" in
-rows) echo "rows set"
rowbool=1
shift
;;
-cols) echo "cols set"
colbool=1
shift
;;
esac
done
if [[ $# -gt 0 ]]
then
fileName=$1
fi
if [[ $# -eq 0 ]]
then fileName=$(stdin)
fi
echo "$fileName"
Related
I am new to shell, and my code takes two arguments from the user. I would like to confirm their arguments before running the rest of the code. I would like a y for yes to prompt the code, and if they type n for no, then the code will ask again for new arguments
Pretty much, if i type anything when I am asked to confirm, the rest of the code runs anyways. I tried inserting the rest of the code after the first then statement, but that didn't work either. I have also checked my code with ShellCheck and it all appears to be legal syntax. Any advice?
#!/bin/bash
#user passes two arguments
echo "Enter source file name, and the number of copies: "
read -p "Your file name is $1 and the number of copies is $2. Press Y for yes N for no " -n 1 -r
echo
if [[ $REPLY =~ ^[Yy]$ ]]
then
echo "cloning files...."
fi
#----------------------------------------REST OF CODE
DIR="."
function list_files()
{
if ! test -d "$1"
then echo "$1"; return;
fi
cd ... || $1
echo; echo "$(pwd)":; #Display Directory name
for i in *
do
if test -d "$i" #if dictionary
then
list_files "$i" #recursively list files
cd ..
else
echo "$i"; #Display File name
fi
done
}
if [ $# -eq 0 ]
then list_files .
exit 0
fi
for i in "$#*"
do
DIR=$1
list_files "$DIR"
shift 1 #To read next directory/file name
done
if [ ! -f "$1" ]
then
echo "File $1 does not exist"
exit 1
fi
for ((i=0; i<$2; i++))
do
cp "$1" "$1$i.txt"; #copies the file i amount of times, and creates new files with names that increment by 1
done
status=$?
if [ "$status" -eq 0 ]
then
echo 'File copied succeaful'
else
echo 'Problem copying'
fi
Moving the prompts into a while loop might help here. The loop will re-prompt for the values until the user confirms them. Upon confirmation, the target code will be executed and the break statement will terminate the loop.
while :
do
echo "Enter source file name:"
read source_file
echo "Number of copies"
read number_of_copies
echo "Your file name is $source_file and the number of copies is $number_of_copies."
read -p "Press Y for yes N for no " -n 1 -r
if [[ $REPLY =~ ^[Yy]$ ]]; then
echo "cloning files...."
break ### <<<---- terminate the loop
fi
echo ""
done
#----------------------------------------REST OF CODE
I have a homework using for loop but I'm not quite understand the task that I have to do in there. I wrote a script but I feel like it's not a correct script. Please help!
Here is the question:
Write a shell script to list out the contents of any directory, and indicate for each file (including invisible ones) whether the file is a directory, a plain file, and whether it is public and/or executable to this process
#!/bin/bash
if [ $# -lt 1 ] ; then
echo " file doesn't exist"
echo
echo " variable needed to run a command"
fi
echo ---------------------------------------------
echo ---------------------------------------------
for i in $*
do
if [ -f $i ]; then
echo " it's a file";
echo "THIS IS A LIST OF FILE and DIRECTORY in $i"
ls -a $i
fi
done
echo -----------------------------------------
if [ -d $i ]; then
echo "directory" ;
echo "THIS IS A LIST OF FILES AND DIRETORY in $i"
ls -a $i
fi
echo ------------------------------------------
if [ -x $i ]; then
echo "executable"
echo "THIS IS A LIST OF EXECUTABLE FILE IN $i"
ls -x $i
fi
echo -----------------------------------------
if [ -r $i ]; then
echo "this file is a public file"
else "this is a private file"
fi
#!/bin/bash
if [ $# -lt 1 ] ; then
echo " file doesn't exist"
echo
echo " variable needed to run a command"
fi
echo ---------------------------------------------
echo ---------------------------------------------
for i in $*
do
if [ -f $i ]; then
echo " it's a file";
echo "THIS IS A LIST OF FILE and DIRECTORY in $i"
ls -a $i
fi
done
echo -----------------------------------------
if [ -d $i ]; then
echo "directory" ;
echo "THIS IS A LIST OF FILES AND DIRETORY in $i"
ls -a $i
fi
echo ------------------------------------------
if [ -x $i ]; then
echo "executable"
echo "THIS IS A LIST OF EXECUTABLE FILE IN $i"
ls -x $i
fi
echo -----------------------------------------
if [ -r $i ]; then
echo "this file is a public file"
else "this is a private file"
fi
Poorly written specifications are the bane of education. "Public" sounds like the wrong word here. I'll assume it means "readable".
You check if there's an argument, but you don't exit the program if there is not. I'd also confirm it's a directory, and readable.
The manual will do you a lot of good. Expect to do a lot of reading till you learn this stuff, and then reference it a lot to be sure.
Read this section carefully, create some tests for yourself to prove they work and that you understand them, and your job will be more than half done.
Don't use [. Generally it's just better to always use [[ instead, unless you are using (( or case or some other construct.
I don't see that a for loop was specified, but it ought to be fine. Just be aware that you might have to specify $1/* and $1/.* separately.
Put all your tests in one loop, though. For each file, test for whether it's a directory - if it is, report it. Test if it's a plain file - if it is, report it.
I do NOT like doing homework for someone, but it looks like you could use an example that simplifies this. I recommend you not use this as written - break it out and make it clearer, but this is a template for the general logic.
#! /bin/env bash
(( $# )) && [[ -d "$1" ]] && [[ -r "$1" ]] || {
echo "use: $0 <dir>" >&2
exit 1
}
for e in "$1"/.* "$1"/*
do echo "$e:"
[[ -d "$e" ]] && echo " is a directory"
[[ -f "$e" ]] && echo " is a plain file"
[[ -r "$e" ]] && echo " is readable"
[[ -x "$e" ]] && echo " is executable"
done
If you read the links I provided you should be able to break this apart and understand it.
Generally, your script is long and a bit convoluted. Simpler is easier to understand and maintain. For example, be very careful about block indentation to understand scope.
$: for i in 1 2 3
> do echo $i
> done
1
2
3
$: echo $i
3
Compare this to -
for i in $*
do if [ -f $i ]; then
echo " it's a file";
echo "THIS IS A LIST OF FILE and DIRECTORY in $i"
ls -a $i
fi
done
echo -----------------------------------------
if [ -d $i ]; then
echo "directory" ;
echo "THIS IS A LIST OF FILES AND DIRETORY in $i"
ls -a $i
fi
You are testing each entry to see if it is a file, and if it is, reporting "THIS IS A LIST OF FILE and DIRECTORY in $i" every time...
but then only testing the last one to see if it's a directory, because the [ -d $i ] is after the done.
...did you run this somewhere to try it, and look at the results?
I am dealing with sorting words in Bash according to a given argument. I am given either argument -r, -a , -v or -h and according to it there are options to sort the words, as you can see at my "help".
Somehow, if I pass the argument -r it creates an error. I really don't understand what I am doing wrong, as if[["$arg"=="-a"]] works, but I have to use case somehow.
Here is my code:
#!/bin/bash
# Natalie Zubkova , zubkonat
# zubkonat#cvut.fel.cz , LS
#help
help="This script will calculate occurances of words in a given file, and it will sort them according to the given argument in following order> \n
without parametre = increasing order according to a number of occurance\n
-r = decreasing order according to a number of occurance\n
-a = in alphabetical increasing order\n
-a -r = in alphabetical decreasing order\n
There are also special cases of the given parametre, when the script is not sorting but:\n
-h = for obtaining help \n
-v = for obtaining a number of this task "
# this function will divide a given chain into a words, so we can start calculating the occurances, we also convert all the capital letters to the small ones by - tr
a=0;
r=0;
EXT=0;
if [ "$1" == "-h" ]; then
echo $help
exit 0
fi
if [ "$2" == "-h" ]; then
echo $help
exit 0
fi
if [ "$1" == "-v" ]; then
echo "5"
exit 0
fi
if [ "$2" == "-v" ]; then
echo "5"
exit 0
fi
function swap {
while read x y; do
echo "$y" "$x";
done
}
function clearAll {
sed -e 's/[^a-z]/\n/gI' | tr '[A-Z]' '[a-z]' | sort | uniq -c |awk '{i++; if(i!=1) print $2" "$1}' #swap
}
for arg do
case "$arg" in
"-a")
a=1
;;
"-r")
r=1
;;
"-v")
echo "5" #number of task is 5
exit 0
;;
"-h")
echo $help
exit 0
;;
"-?")
echo "invalid parametre, please display a help using argument h"
exit 0
;;
esac
done
#Sort according to parametres -a and -r
function sortWords {
if [[ a -eq 1 ]]; then
if [[ r -eq 0 ]]; then
clearAll | sort -nk1
fi
fi
if [[ a -eq 1 ]]; then
if [[ r -eq 1 ]]; then
clearAll | sort -nk1 -r
fi
fi
if [[ r -eq 1 ]]; then
if [[ a -eq 0 ]]; then
clearAll | sort -nk2 -r
fi
fi
if [[ a -eq 0 ]]; then
if [[ r -eq 0 ]]; then
clearAll | sort -nk2
fi
fi
}
#code is from Stackoverflow.com
function cat-all {
while IFS= read -r file
do
if [[ ! -z "$file" ]]; then
cat "$file"
fi
done
}
#histogram
hist=""
for arg do
if [[ ! -e "$arg" ]]; then
EXT=1;
echo "A FILE DOESNT EXIST" >&2
continue;
elif [[ ! -f "$arg" ]]; then
EXT=1;
echo "A FILE DOESNT EXIST" >&2
continue;
elif [[ ! -r "$arg" ]]; then
EXT=1;
echo "A FILE DOESNT EXIST" >&2
continue;
fi
done
for arg do
hist="$hist""$arg""\n"
done
echo -e "$hist" | cat-all | sortWords
exit $EXT;
Here is what our upload system which does some test to see if our program works says:
Test #6
> b5.sh -r ./easy.txt
ERROR: script output is wrong:
--- expected output
+++ script stdout
## --- line 1 (167 lines) ; +++ no lines ##
-the 89
-steam 46
-a 39
-of 37
-to 35
...
script written 484 lines, while 484 lines are expected
script error output:
A FILE DOESNT EXIST
cat: invalid option -- 'r'
Try `cat --help' for more information.
script exit value: 1
ERROR: Interrupted due to failed test
If anyone could help me I would really appreciate it.
You forgot to move the parameter index position with shift:
"-r")
r=1
shift
;;
shift above moves to the next command line arg: ./easy.txt in your case.
Without it, read -r file will read -r instead of the file name.
I am writing a bash script to finger the first three line of user's info.
ex:
$ ./c.sh bob unknown
Login: bob Name: Bob
Directory: /u1/h7/bob Shell: /bin/tcsh
Office: AA 044, x8361 Home Phone: 000-000-0000
unknown: no such user.
Here is my code so far
#!/bin/bash
if [ $# == 0 ]; then
echo "Usage: ./c.sh Login/Username"
exit
else
i=$#
j=1
while [ "$j" -le "$i" ]; do
finger ${$j} | head -n+3
echo
j=$(($j+1))
done
fi
instead of giving what user types for the command line arguments, ${$j} is giving me the the value of $j, any suggestion and help for how to get the login/username? I've tried $($j), $((j)), ${$j}....
The easy answer: stop using unnecessary indirection:
#!/bin/bash
if (( $# == 0 )); then
echo "Usage: ./c.sh Login/Username"
exit
else
while [[ $1 ]]; do
finger "$1" | head -n+3
echo
shift
done
fi
or…
…
for user; do # equivalent to `for user in "$#"; do`
finger "$user" | head -n+3
…
done
You could write it this way:
i=$#
j=1
while [ $j -le $i ]; do
finger "${#:j++:1}" | head -n+3
echo
done
…but you don't need to work that hard.
#!/bin/bash
if [[ $# -eq 0 ]]; then
echo "Usage: $0 Login/Username"
exit
else
for ARG in "$#"; do
finger "$ARG" | head -n 3
echo # If you want a newline
done
fi
As simple as it can be.
for var in "$#"
do
if test -z $var
then
echo "missing operand"
elif [ -d $var ]
then
echo "This is a directory"
elif [ ! -f $var ]
then
echo "The file does not exist"
else
basename=$(basename $var)
dirname=$(readlink -f $var)
inodeno=$(ls -i $var| cut -d" " -f1)
read -p "remove regular file $#" input
if [ $input = "n" ]
then exit 1
fi
mv $var "$var"_"$inodeno"
echo "$basename"_"$inodeno":"$dirname" >> $HOME/.restore.info
mv "$var"_"$inodeno" $HOME/deleted
fi
done
**Hello, the above code is trying to mimic the rm command in unix. Its purpose is to remove the file .
Eg if I type in bash safe_rm file1 , it works however if type in
bash safe_rm file1 file 2 , it prompts me to remove file 1 twice and gives me a unary operater expected for line 27(if [ $input = "n" ]).
Why does it not work for two files, ideally I would like it to prompt me to remove file1 and file 2.
Thanks
read -p "remove regular file $#" input
should probably be
read -p "remove regular file $var" input
That's the basic.
And this is how I'd prefer to do it:
for T in "$#"; do
if [[ -z $T ]]; then
echo "Target is null."
elif [[ ! -e $T ]]; then
echo "Target does not exist: $T"
elif [[ -d $T ]]; then
echo "Target can't be a directory: $T"
else
BASE=${T##*/}
DIRNAME=$(exec dirname "$T") ## Could be simpler but not sure how you want to use it.
INODE_NUM=$(exec stat -c '%i' "$T")
read -p "Remove regular file $T? "
if [[ $REPLY == [yY] ]]; then
# Just copied. Not sure about its logic.
mv "$T" "${T}_${INODE_NUM}"
echo "${BASE}_${INODE_NUM}:${DIRNAME}" >> "$HOME/.restore.info"
mv "${T}_${INODE_NUM}" "$HOME/deleted"
fi
fi
done