Strings are typically delimited by quotes, which raises the problem of dealing with strings that include quotes.

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2
votes
2answers
4k views

Passing a variable to sed

I cannot not use a shell variable in sed in the $NUMBER form. I have this line in my shell script: cat shared.txt sed 's/whatever1/$2 ... whatever2/' > shared2.txt The result in shared2.txt ...
14
votes
1answer
2k views

Delete all files starting with a question mark

I have a folder in which I have around 4k files. Some of these files start with a a ? or ! character. I need to delete them but can't find an expression that would do so: rm -f ./?* just deletes ...
3
votes
2answers
1k views

How to prevent command injection through command options?

I have an wrapper application where I need to let the user specify custom options to pass to a simulator. However, I want to make sure the user doesn't inject other commands through the user options. ...
2
votes
2answers
528 views

Bad substitution inside xargs subshell?

I'm using this command to process PNG files: find . -iname "*png" -print0 | xargs -r0 --max-procs=4 -n1 sh -c 'pngnq -s1 $1 && advpng -z -4 -q ${$1%.*}-nq8.png' - It seems to actually work ...
1
vote
1answer
2k views

Executable symbolic link file not working

On Mac OSX, I am having trouble with a pretty simple thing. My symbolic link doesn't want to execute. Can you help me spot the trouble? Thanks! $ echo $PATH ...
0
votes
3answers
98 views

I need to turn a series of commands piped together into an alias in .bashrc

sudo ifconfig wlan0 | grep 'inet addr:' | cut -d: -f2 | awk '{ print $1}' The above command when run from terminal outputs the right "internal" ip address. When I try to pass as alias like: alias ...
5
votes
2answers
527 views

Quoted vs unquoted string expansion

for i in $(xrandr); do echo "$i" ; done for i in "$(xrandr)"; do echo "$i"; done for i in "$(xrandr)"; do echo $i; done I understand why 1 differs from 2. But why does 3 give a different output ...
1
vote
1answer
157 views

Prompt user for sentence and store it without being disturbed by spaces

I have a bash function that prompts user to input certain data. I tried it with first name, last name, birthday etc. Data that is mostly represented in one sentence. When I ask for street + no. the ...
1
vote
1answer
443 views

7z getting an event not found error in command line

I am using 7zip on my centos machine and ziping a file via command line. This is my syntax 7za a -t7z backup.7z public_html\ -mx0 -xr!restricted_area What i'm expecting with this syntax is to ...
2
votes
2answers
892 views

Pass arguments to function exactly as-is

I have the following function: bar() { echo $1:$2; } I am calling this function from another function, foo. foo itself is called as follows: foo "This is" a test I want to get the following ...
2
votes
4answers
3k views

sh and grep numbers only

I'm facing a problem and trying to find a solution that works in sh. If I could use bash this code would work: ls /a|grep ^[0-9] Unfortunately this is not the case with sh, and yes I need to use ...
0
votes
1answer
191 views

Unexpected whitespace using sqsh in command substitution [closed]

Below shell script instruction behave in weird way ARG_DATE=`sqsh -S $SERVER -U $DB_USER -P $DB_PASSWORD -D dbname -h<<END SET NOCOUNT ON go select convert(varchar, PRIOR_COB_DATE, 112) from ...
1
vote
2answers
130 views

Bash variable into html

I have a script that gets the filenames in a folder and creates HTML link to them on my homepage. Here is the script: #!/bin/bash list_dir=`ls -t /path/to/dir/` for i in $list_dir do echo ...
3
votes
1answer
84 views

find utility does not recognize bracket notation

I've two files in the current folder: submitWeb.m submit.m the following find does not show the two files: find . -regex .*submit\(Web\)?\.m But the above regex expression works fine in ...
0
votes
2answers
172 views

sqlite fts quoting problem

I can do this in sqlite tool: sqlite> select caption from notes_fts where notes_fts MATCH '"perl install"'; but cannot from the Linux shell i.e., this fails: user@host:~$ sqlite3 sqldb ...
1
vote
5answers
5k views

bash execute read command from file

After some manipulations, I got the file with commands that I would be glad to be able to execute. Input file (name of file is inp2.txt): "02 - Beautiful Emptiness.mp3" "02 - Come. mp3" "02 - Go ...
0
votes
1answer
1k views

shell scripting escaping madness - sending single quotes to subshell

I'm beyond my skill level in getting this to work properly... #!/bin/bash -x # mxfbc.sh - mxf video file batch converter # pass at the command line ... # (1) the directory to batch convert (typically ...
2
votes
3answers
648 views

Very strange behavior with grep and IFS

I'm having trouble using grep, the returned results are "n-empty", I mean without the 'n' character... This is the script sample : OLDIFS=$IFS IFS="\\n" i=$(grep -ril $1 *) echo $i IFS=$OLDIFS ...
6
votes
2answers
347 views

Bash : command line with optional arguments

I'm running this kind of code: #!/usr/bin/env bash set -u exclude1='--exclude=/path/*' exclude2='--exclude=/path with spaces/*' exclude3='' # any 'exclude' can be empty tar -czf backup.tgz ...
2
votes
3answers
286 views

Can I reload variable in a watch command?

Part of my job involves some data handling. One of the tasks is to 'flatten' a set of directories (which we'll call Dir for now), and copy them to a new location called DirFlat. This can take a long ...
2
votes
1answer
109 views

replacement inside parallel command string

I want to download multiple files and save them to the md5 sum of its name: cat list | parallel -j4 "md5=$(wget -O - {} | tee tmpfile_{#} | md5sum | cut -d ' ' -f 1); mv tmpfile_{#} $md5" but the ...
4
votes
5answers
394 views

How to use ' in alias?

I have one-line that I want to call using alias. while printf '%s ' "$(df -P / | awk 'NR==2 { print $(NF-1) }')"; do sleep 30; done I tried to escape ' like \' but it didn't work. What is the ...
2
votes
2answers
1k views

Calling bash from sh (dash) with commands read from args, and “Unterminated quoted string”/“unexpected EOF”

Just thought I'd document this: I'm trying something very simple - set env variable in bash, and print it out: $ bash -c "a=1; echo a$a;" a $ bash -c "a=1; echo a\$a;" a1 Now I'd want this same ...
0
votes
3answers
131 views

Is it the de facto to use the grave (`) symbol, followed by a normal apostraphe (') to quote things?

For example, 'foo bar' would be quoted as `foo bar', or ``foo bar''. Is it encouraged or general practice to use this quoting syntax?
2
votes
3answers
1k views

Treatment of backslashes across shells

How do echo and printf treat backslashes in zsh, bash and other shells? Under zsh I get the following behavior: $ echo "foo\bar\baz" foaaz $ echo "foo\\bar\\baz" foaaz $ echo 'foo\bar\baz' foaaz $ ...
5
votes
2answers
2k views

How do I escape a sub-directory name with an ampersand in it?

Running a kornshell and trying to traverse a directory tree. Want to cd to a sub-directory named as follows: -3ab_&_-3dc.img My question is HOW do I need to escape the ampersand in this name? ...
9
votes
4answers
2k views

How to print “$” in here-document

How can I echo "$" in a here-doc in bash? For example, I want to have a file with the content on remote server like $ABC=home_dir. $ ssh hostname sudo -s <<EOF echo "$ABC=home_dir" > file ...
0
votes
1answer
391 views

Reading a path from a nested grep yields “No such file or directory”

Essentially, I have a file containing the path to another file. A single line looks like this. "/home/self/file" Now, separately... > cat "/home/self/file" blah blah ... > grep '".*"' ...
30
votes
3answers
6k views

using single or double bracket - bash

I'm confused with using single or double bracket. look at code: dir="/home/mazimi/VirtualBox VMs" if [[ -d ${dir} ]]; then echo "yep" fi It works perfectly although the string contains space. ...
6
votes
2answers
401 views

Why does --text=“$@” only pass the first word?

When I run the following script with some arguments like arg1 arg2 arg3: #!/bin/bash zenity --entry --text="$@" zenity creates an entry dialog with this text: "arg1" whereas I expect "arg1 arg2 ...
1
vote
1answer
242 views

How to prevent double escaping?

I'm trying to put a bunch of images together into a pdf. I ran gm convert *.jpg out.pdf and it worked, but the images were not in the right order. I found that ls -v orders them correctly so then I ...
8
votes
1answer
914 views

Wildcards inside quotes

This will be an easy one, but in my memories, when shell scripting, using double quotes would allow expanding globbing and variables. But in the following code: #!/bin/sh echo *.sh echo "*.sh" echo ...
2
votes
2answers
453 views

Use a parameter in a command argument

I run a find command to search files with a name containing perl: find /tmp -name '*perl*' /tmp/perl.pl /tmp/run-perl-stage.pl But when I set the perl name in a variable PARAMETER and run the find ...
1
vote
3answers
10k views

How to tell grep to match special character at beginning of each word [duplicate]

I have certain questions regarding grep. Why does the following command match '<Hello'? $ grep -E "\<H" test Hello World <Hello H<ello What needs to be done to match '<Hello' only? ...
2
votes
2answers
938 views

Use of quotes in GNU grep regular expressions

I could see that certain patterns in the GNU Grep can be enclosed within brackets and certain others need not be. For example, matching the beginning of a word works only if it is enclosed within ...
2
votes
2answers
581 views

How to pass the output of a script to a command like ls without the output being split?

Suppose I have a script like this: #!/bin/bash printf '%q\n' "b c" Executing the script prints: b\ c on the commandline. Now, being in a directory which contains a file named b c I want to pass ...
2
votes
1answer
181 views

Confused about when to escape metacharacters in pathnames

I'm pretty confused about under which circumstances do I need to escape metacharacters in pathnames. Consider the following example: I'm in the following working directory: $ echo $PWD ...
9
votes
5answers
1k views

Why do I need to quote variable for if, but not for echo?

I've read that you need double quotes for expanding variables, e.g. if [ -n "$test" ]; then echo '$test ok'; else echo '$test null'; fi will work as expected, while if [ -n $test ]; then echo ...
2
votes
1answer
245 views

tcsh vs zsh. Escape/control characters

I am having problems running this command to work in zsh: my_command -u something -s X:^0 The command works right away on tcsh, but on zsh I get: zsh: no matches found -s X:^0 This made me ...
1
vote
1answer
110 views

Frequent command “template”: remove parameter expansion escape characters

zsh newbie here... I find myself using a handful of long commands over and over again with slightly different arguments. For example: rsync -havu --progress --rsh='ssh -l mylogin' ...
3
votes
3answers
210 views

Zsh function with su and echo

I'm trying to add a function to my .zshrc that makes adding new USE flags to my /etc/portage/package.use file easier. Normally, I'd have to do su -c 'echo "net-misc/aria2 bash-completion bittorrent" ...
38
votes
2answers
4k views

$VAR vs ${VAR} and to quote or not to quote

I can write VAR=$VAR1 VAR=${VAR1} VAR="$VAR1" VAR="${VAR1}" the end result to me all seems about the same. Why should I write one or the other? are any of these not portable/POSIX?
5
votes
2answers
818 views

Bash prompt not recognizing Unicode escapes

I'm trying to customize my Bash prompt with Unicode characters and I'm having a bit of trouble. If I try to include a Unicode character like this: $ echo ☢ | hexdump -C 00000000 e2 98 a2 0a ...
3
votes
2answers
3k views

Read a file and copy to another file

I'm having a issue, I need to copy the file contents and remove a couple of lines if they match the output from a previous command. But so far, I'm having an issue in maintaining the file lines ...
3
votes
1answer
175 views

Escaping quotes for scp

I needed to write a that behaves correctly with nasty (spaces, braces, etc..) filenames. scp -rv "$1" shiny:/Volumes/Seagate3To/\"$1\" This function works, but I don't understand why the quotes ...
1
vote
2answers
203 views

How to scp folders with nasty names using a shell function

I am trying to write a function that I will put on all my machines in order to make it easy to send files at a fixed place on my network. Here is my script so far. Some folder may have duplicates ...
2
votes
1answer
927 views

permission denied executing script over ssh

When a web page is loaded on server A i want it to run a script on server B. I can do this with a series of commands from server A by logging into server B and executing the script, but it needs to be ...
1
vote
5answers
2k views

Identify folder in bash

I was trying to learn how to identify only folders within a folder on the main level. example: main -folder 1 -folder 2 -folder 3 I started with this script: #!/bin/bash ...
5
votes
1answer
4k views

Trouble in script with spaces in filename

I've got a script that scp's a file from remote host back to local. Sometimes the file names contain spaces. scp does not like spaces in its file names. For some reason my attempts at handling the ...
2
votes
2answers
91 views

Parameter expansion seems to be missing a piece

I'm currently learning how to write simple scripts and can't get my head around a very simple problem. I have the following command in my script... touch ${DIRECTORY}/${FILE} This command appears ...