On MacOS Catalina, I have a bash script with
if [[ ! -f $CR/home/files/Recovery_*.txt ]]
then
echo "File does not exists in /home/files directory. Exiting" >> $log
echo "Aborted - $CR/home/files/Recovery_*txt not exist"
exit
fi
Even though there are 2 files in the directory the script exits. If I list directory contents beforehand there are 2 files. If I change it as follows the if is skipped:
if [[ `ls -la $CR/home/files/Recovery_*.txt | wc -l` -eq 0 ]]
then
echo "No files are :"
exit
fi
I am wanting to use the if -f conditional.
Any suggestions please?
Cheers, C
If you use nullglob, a glob expression that doesn't match returns an empty string. This lets us count files in bash without spawning other processes. Create an array with the expression, then check its length.
shopt -s nullglob
files=($CR/home/files/Recovery_*.txt)
if [[ ${#files[#]} -eq 0 ]]
then
echo "No files"
exit
fi
[Edited]
The error was not the variables, but the missing shebang as the script has come across from W2K3 SFU.
The tip about shellchecker.net was awesome and I will use that from now.
Thanks.
Related
I'm trying to write a script that will only accept exactly one argument. I'm still learning so I don't understand what's wrong with my code. I don't understand why, even though I change the number of inputs the code just exits. (Note: I'm going to use $dir for later if then statements but I haven't included it.)
#!/bin/bash
echo -n "Specify the name of the directory"
read dir
if [ $# -ne 1 ]; then
echo "Script requires one and only one argument"
exit
fi
You can use https://www.shellcheck.net/ to double check your syntax.
$# tells you how many arguments the script was called with.
Here you have two options.
Option 1: Use arguments
#!/bin/bash
if [[ $# -ne 1 ]]
then
echo "Script requires one and only one argument"
exit 1
else
echo "ok, arg1 is $1"
fi
To call the script do: ./script.bash argument
Use [[ ]] for testing conditions (http://mywiki.wooledge.org/BashFAQ/031)
exit 1: by default when a script exists with a 0 status code, it means it worked ok. Here since it is an error, specify a non-zero value.
Option 2: Do not use arguments, ask the user for a value.
Note: this version does not use arguments at all.
#!/bin/bash
read -r -p "Specify the name of the directory: " dir
if [[ ! -d "$dir" ]]
then
echo "Error, directory $dir does not exist."
exit 1
else
echo "ok, directory $dir exists."
fi
To call the script do: ./script.bash without any arguments.
You should research bash tutorials to learn how to use arguments.
I currently have a directory that is supposed to have 500 files. Each file is of the name form List.1.rds, ... List.500.rds. The way I can see which ones are missing is by the following code in bash:
for((i=1; i<=500; i++)); do name="List.${i}.rds"; [[ ! -e "$name" ]] && echo "missing $name"; done
If a file is missing, it returns the missing file name. However, I would like to go one step further and stop the entire script should any file be missing. Is there a way to do this? thanks.
It can be as simple as setting a flag when a file is missing:
miss=0
for ((i=1;i<=500;i++)); do
file=List.$i.rds
if [[ ! -e $file ]]; then
echo "Missing $file"
miss=1
fi
done
# exit if "miss" flag is 1
((miss)) && exit 1
This a small bash program that is tasked with looking through a directory and counting how many files are in the directory. It's to ignore other directories and only count the files.
Below is my bash code, which seems to fail to count the files specifically in the directory, I say this because if I remove the if statement and just increment the counter the for loop continues to iterate and prints 4 in the counter (this is including directories though). With the if statement it prints this to the console.
folder1 has files
Looking at other questions I think the expression in my if statement is right and I am getting no compilation errors for syntax or another problems.
So I just simply dumbfounded as to why it is not counting the files.
#!/bin/bash
folder=$1
if [ $1 = empty ]; then
folder=empty
counter=0
echo $folder has $counter files
exit
fi
for d in $(ls $folder); do
if [[ -f $d ]]; then
let 'counter++'
fi
done
echo $folder has $counter files
Thank you.
Your entire script could be very well simplified as below with enhancements made. Never use output of ls programmatically. It should be used only in the command-line. The -z construct allows to you assert if the parameter following it is empty or non-empty.
For looping over files, use the default glob expansion provided by the shell. Note the && is a short-hand to do a action when the left-side of the operand returned a true condition, in a way short-hand equivalent of if <condition>; then do <action>; fi
#!/usr/bin/env bash
[ -z "$1" ] && { printf 'invalid argument passed\n' >&2 ; exit 1 ; }
shopt -s nullglob
for file in "$1"/*; do
[ -f "$file" ] && ((count++))
done
printf 'folder %s had %d files\n' "$1" "$count"
dir1='/d/Dropbox/PhD/Experimental Design/APS/Processed_and_Graphed/InvariantQ'
echo $dir1
for f in A*.xlsx
do
str2=${f%?????}
if [[ ! -d $dir1/$str2 ]]; then
mkdir $dir1/$str2
else
echo "Directory" $dir1/$str2 "already exists, directory not created"
fi
if [[ ! -f $dir1/$str2/$f ]]; then
mv -v $f $dir1/$str2
else
echo "File" $dir1/$str2/$f "already exists, file not copied"
fi
done
I'm trying to get the following script to run, however when it attempts to mkdir $dir1/$str2, it creates:
/d/Dropbox/PhD/Experimental
and returns back the error:
create directory '/d/Dropbox/PhD/Experimental': file exists
create directory 'Design/APS/Processed_and_Graphed/InvariantQ': no such file or directory
I've tried coding the directory name with double quotations, or a '\' in front of the space in 'Experimental Design', but neither method seems to work... It seems this can be achieved in batch files using "usebackq" -is there a way to do this in GitBash for windows? If so, where in my code would it be applied?
Also, is anyone aware as to why testing a statement here using "[[" works, whereas a single "[" doesn't?
Quote your variables to prevent word splitting on the expansion.
dir1='/d/Dropbox/PhD/Experimental Design/APS/Processed_and_Graphed/InvariantQ'
echo "$dir1"
for f in A*.xlsx
do
str2=${f%?????}
if [[ ! -d $dir1/$str2 ]]; then
mkdir "$dir1/$str2"
else
echo "Directory $dir1/$str2 already exists, directory not created"
fi
if [[ ! -f $dir1/$str2/$f ]]; then
mv -v "$f" "$dir1/$str2"
else
echo "File $dir1/$str2/$f already exists, file not copied"
fi
done
It works with [[ because this is shell syntax, not an ordinary command. It recognizes variables specially and doesn't do work splitting on them. This is the same reason that it allows you to use operators like < without quoting them.
I'm writing a reasonably lengthy script (or what I would consider lengthy - you could probably do it in a few hours). I basically have a file (named .restore.info) which contains files of names. In part of the script, I want to test "If cannot find filename in .restore.info, then says “Error: restored file does not exist”. Apologies if this doesn't make sense for you guys (for me, it does in the grand scheme of things). So if type this in the command line:
sh MYSCRIPT filename
It will search for the string filename in the .restore.info file, and if it cant find anything, it should produce an error message.
Basically, I need the top line of this coded translated into a UNIX bash statement and something that actually makes sense!:
If grep $1 .restore.info returns an exist status of 1; then
echo “Filename does not exist!”
fi
Thanks in advance! Please ask me if you need me to clarify anything more clearly as I know I'm not the best explainer, and I'll get back to you in less than a minute! (+rep and best answer of course will be given!)
You probably only care if grep exits with a non-zero exit status:
if ! grep -q "$1" .restore.info; then
echo "Filename does not exist!"
fi
but if you really do care about a specific exit status (1, in this case):
if ! grep -q "$1" .restore.info && [[ $? -eq 1 ]]; then
echo "Filename does not exist!"
fi
Use grep -q
grep -q "filename" .restore.info && echo "found match"
or
! grep -q "filename" .restore.info && echo "not found"
grep -l 'filename' .restore.info
if [ $? = 0 ];then
echo "found it"
else
echo "not found"
fi