I have this
if [[ -e file.jpg ]] ;then echo "aaaaaaaaa"; fi
and it prints "aaaaaaa"
but I want to print if there is file.png or file.png also
so I need something like this
if [[ -e file.* ]] ;then echo "aaaaaaaaa"; fi
but it doesn't work I am missing something in the syntax
Thanks
If you enable bash's nullglob setting, the pattern file.* will expand to an empty string if there are no such files:
shopt -s nullglob
files=(file.*)
# now check the size of the array
if (( ${#files[#]} == 0 )); then
echo "no such files"
else
echo "at least one:"
printf "aaaaaaaaa %s\n" "${files[#]}"
fi
If you do not enable nullglob, then files=(file.*) will result in an array with one element, the string "file.*"
Why not use a loop ?
for i in file.*; do
if [[ -e $i ]]; then
# exists...
fi
done
Related
I am very new to Bash Scripting and I have a question regarding my CheckOurCodingRules.sh script:
I want to search for every 'hPar,' in a textfile and if found it should be checked if there is a also a 'const' in the same row.
Thats what I got so far but there is something wrong here:
while read line
do
if [[ $line == *hPar\,* ]] && [[ $line == *const\*]];then
DOCUMENTATION_TEST_A=1
else
echo DOCUMENTATION_TEST_A=0
fi
done < $INPUT_FILE
if [[DOCUMENTATION_TEST_A=0]];then
echo "error: Rule1: No const before hpar"
fi
There are a couple of issues with your script, see the code below which works for me:
DOCUMENTATION_TEST_A=0 # initial value
while read line
do
# spaces between conditional and brackets, no backslashes
if [[ $line == *hPar,* ]] && [[ $line == *const* ]]
then
DOCUMENTATION_TEST_A=1
break # optional, no need to scan the rest of the file
fi
done < $INPUT_FILE
# spaces and $, -eq is used for numerical comparisons
if [[ $DOCUMENTATION_TEST_A -eq 0 ]];
then
echo "error: Rule1: No const before hpar"
fi
A cleaner solution would be to use grep:
if ! grep "hPar," $INPUT_FILE | grep "const" >/dev/null
then
echo "error: Rule1: No const before hpar"
fi
I am writing a shell script to read all the files in the give directory by the user input then count how many files with that extension. I just started learning Bash and I am not sure why it this not locating the files or reading the directory. I am only putting 2 example but my count is always 0.
This is how I run my script
$./check_ext.sh /home/user/temp
my script check_ext.sh
#!/bin/bash
count1=0
count2=0
for file in "ls $1"
do
if [[ $file == *.sh ]]; then
echo "is a txt file"
(( count1++ ))
elif [[ $file == *.mp3 ]]; then
echo "is a mp3 file"
(( count2++ ))
fi
done;
echo $count $count2
"ls $1" doesn't execute ls on $1, it just a plain string. Command substitution syntax is $(ls "$1")
However there is no need to use ls, just use globbing:
count1=0
count2=0
for file in "$1"/*; do
if [[ $file == *.sh ]]; then
echo "is a txt file"
(( count1++ ))
elif [[ $file == *.mp3 ]]; then
echo "is a mp3 file"
(( count2++ ))
fi
done
echo "counts: $count1 $count2"
for file in "$1"/* will iterate through all the files/directories in the directory denoted by $1
EDIT: For doing it recursively inside a directory:
count1=0
count2=0
while IFS= read -r -d '' file; do
if [[ $file == *.sh ]]; then
echo "is a txt file"
(( count1++ ))
elif [[ $file == *.mp3 ]]; then
echo "is a mp3 file"
(( count2++ ))
fi
done < <(find "$1" -type f -print0)
echo "counts: $count1 $count2"
POSIXly:
count1=0
count2=0
for f in "$1"/*; do
case $f in
(*.sh) printf '%s is a txt file\n' "$f"; : "$((count1+=1))" ;;
(*.mp3) printf '%s is a mp3 file\n' "$f"; : "$((count2+=1))" ;;
esac
done
printf 'counts: %d %d\n' "$count1" "$count2"
You can use Bash arrays for this too: if you only want to deal with extensions sh and mp3:
#!/bin/bash
shopt -s nullglob
shs=( "$1"/*.sh )
mp3s=( "$1"/*.mp3 )
printf 'counts: %d %d\n' "${#shs[#]}" "${#mp3s[#]}"
If you want to deal with more extensions, you can generalize this process:
#!/bin/bash
shopt -s nullglob
exts=( .sh .mp3 .gz .txt )
counts=()
for ext in "${exts[#]}"; do
files=( "$1"/*."$ext" )
counts+=( "${#files[#]}" )
done
printf 'counts:'
printf ' %d' "${counts[#]}"
echo
If you want to deal with all extensions (using associative arrays, available in Bash ≥4)
#!/bin/bash
shopt -s nullglob
declare -A exts
for file in "$1"/*.*; do
ext=${file##*.}
((++'exts[$ext]'))
done
for ext in "${!exts[#]}"; do
printf '%s: %d\n' "$ext" "${exts[$ext]}"
done
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"
I need to check if a file with a specific extension exists and if it is not empty.
The problem is that I don't know the name of the file, just the extension and the path.
Here my solution with an known name
FILE="/Users/test/my.out"
if [[ -f $FILE && -s $FILE ]] ; then echo "EXIST"; fi
Using
FILE="/Users/test/*.out"
Do not work
I suggest you use an array, in case there are multiple files:
arr=( /Users/test/*.out )
if (( ${#arr[#]} > 0 )) && [[ -s "${arr[0]}" ]]
then
...
fi
You can either use #dogbane's solution using an array or use a loop:
dir=/users/test
for file in "${dir}"/*.out; do
break
done
if [ -f "${file}" ] && [ -s "${file}" ]; then
echo "found a regular, non-empty .out file: ${file}"
fi
I think this should do:
if [ -f ${var} ]; then
if [ -s ${var} ]; then
echo "Found $var"
fi
fi
Try
FILE=$(ls "Downloads/*.zip" 2>/dev/null)
Only works, if there is only a single file.
How does one test for the existence of files in a directory using bash?
if ... ; then
echo 'Found some!'
fi
To be clear, I don't want to test for the existence of a specific file. I would like to test if a specific directory contains any files.
I went with:
(
shopt -s dotglob nullglob
existing_files=( ./* )
if [[ ${#existing_files[#]} -gt 0 ]] ; then
some_command "${existing_files[#]}"
fi
)
Using the array avoids race conditions from reading the file list twice.
From the man page:
-f file
True if file exists and is a regular file.
So:
if [ -f someFileName ]; then echo 'Found some!'; fi
Edit: I see you already got the answer, but for completeness, you can use the info in Checking from shell script if a directory contains files - and lose the dotglob option if you want hidden files ignored.
I typically just use a cheap ls -A to see if there's a response.
Pseudo-maybe-correct-syntax-example-ahoy:
if [[ $(ls -A my_directory_path_variable ) ]] then....
edit, this will work:
myDir=(./*) if [ ${#myDir[#]} -gt 1 ]; then echo "there's something down here"; fi
You can use ls in an if statement thus:
if [[ "$(ls -a1 | egrep -v '^\.$|^\.\.$')" = "" ]] ; then echo empty ; fi
or, thanks to ikegami,
if [[ "$(ls -A)" = "" ]] ; then echo empty ; fi
or, even shorter:
if [[ -z "$(ls -A)" ]] ; then echo empty ; fi
These basically list all files in the current directory (including hidden ones) that are neither . nor ...
If that list is empty, then the directory is empty.
If you want to discount hidden files, you can simplify it to:
if [[ "$(ls)" = "" ]] ; then echo empty ; fi
A bash-only solution (no invoking external programs like ls or egrep) can be done as follows:
emp=Y; for i in *; do if [[ $i != "*" ]]; then emp=N; break; fi; done; echo $emp
It's not the prettiest code in the world, it simply sets emp to Y and then, for every real file, sets it to N and breaks from the for loop for efficiency. If there were zero files, it stays as Y.
Try this
if [ -f /tmp/foo.txt ]
then
echo the file exists
fi
ref: http://tldp.org/LDP/abs/html/fto.html
you may also want to check this out: http://tldp.org/LDP/abs/html/fto.html
How about this for whether directory is empty or not
$ find "/tmp" -type f -exec echo Found file {} \;
#!/bin/bash
if [ -e $1 ]; then
echo "File exists"
else
echo "Files does not exist"
fi
I don't have a good pure sh/bash solution, but it's easy to do in Perl:
#!/usr/bin/perl
use strict;
use warnings;
die "Usage: $0 dir\n" if scalar #ARGV != 1 or not -d $ARGV[0];
opendir my $DIR, $ARGV[0] or die "$ARGV[0]: $!\n";
my #files = readdir $DIR;
closedir $DIR;
if (scalar #files == 2) { # . and ..
exit 0;
}
else {
exit 1;
}
Call it something like emptydir and put it somewhere in your $PATH, then:
if emptydir dir ; then
echo "dir is empty"
else
echo "dir is not empty"
fi
It dies with an error message if you give it no arguments, two or more arguments, or an argument that isn't a directory; it's easy enough to change if you prefer different behavior.
# tested on Linux BASH
directory=$1
if test $(stat -c %h $directory) -gt 2;
then
echo "not empty"
else
echo "empty"
fi
For fun:
if ( shopt -s nullglob ; perl -e'exit !#ARGV' ./* ) ; then
echo 'Found some!'
fi
(Doesn't check for hidden files)