5
votes
3answers
399 views

What is the difference having double quotes or not in bash [duplicate]

I have some bash scripts, one which has the following content: #!/bin/bash source $(dirname ${BASH_SOURCE[0]})/script.sh while the other one has the following content: #!/bin/bash source ...
1
vote
2answers
43 views

About escape with SSH pipe

I want to execute the awk command with long parameters,like this: ssh host "netstat -rn|awk 'NR!=1 && NF>=6 && $1!="Destination" {printf "%-15s %-20s\n", $1, $2}'|sort -f " but ...
0
votes
4answers
55 views

bash event not found trying to match and exclude parenthesis in grep

In a very long line I'll summarize with: (foo),(bar,baz(word,right),(end) I want to print only: (bar,baz(word,right To match the second parenthesis, I exclude the word that follows the ...
1
vote
2answers
29 views

Why my tabs are not expanding in TIMEFORMAT?

I need to measure the running time of an application, so I'm messing with TIMEFORMAT in order to print short format with the maximum precision available. From the Bash Refence Manual: TIMEFORMAT ...
1
vote
2answers
44 views

Bash script is not working

I wanted to create a script that executes the ls command with the provided arguments. Why isn't it working? I tried running it with for example -R, then it echoes (I echoed the same thing for ...
5
votes
1answer
112 views

understanding the default value of IFS

In my GNU bash version 4.2.8, IFS has a default value of space, tab and line feed by default: usr@T42 ~ $ echo -n "$IFS" | hexdump -C 00000000 20 09 0a | ..| ...
1
vote
1answer
75 views

Pass bash script arguments in double quotes to php cli script

I am trying to pass arguments to a bash script and then to a php script, I have literally looked at 30+ links, and tried over a dozen examples, and I for whatever reason have not been able to get the ...
15
votes
2answers
324 views

Quoting within $(command substitution) in Bash

In my Bash environment I use variables containing spaces, and I use these variables within command substitution. Unfortunately I cannot find the answer on SE. What is the correct way to quote my ...
2
votes
2answers
105 views

Why does bash add single quotes to unquoted failed pathname expansions in a command before executing it?

I was exploring the tracing of commands using set -x (set +x to unset) in bash: Print a trace of simple commands, for commands, case commands, select commands, and arithmetic for commands and ...
5
votes
4answers
104 views

How to quote a string containing dollar sign $ and single quote '?

My directory's name contains a $ and ', for example :~$ export DIR=\$my\'dir :~$ sh -c "ls $DIR" How can I run above command without $my being expanded? I know the single quote doesn't work since ...
1
vote
1answer
50 views

Assignment to variables

I was trying to devise a solution to a different question asked on the site and came across this curious issue. Here is the set of commands that I issued: $ foo=82a9948422 $ echo $foo 82a9948422 $ ...
3
votes
1answer
52 views

variable expansion within command substitution over SSH bash 4.X

I want to do this ssh ${w100user}@web100 'ls -l "$(grep "${1}" /etc/pure-ftpd/pureftpd.passwd|cut -d':' -f6)"' Which obviously performs an ssh session to server web100 as w100user and then greps ...
1
vote
2answers
55 views

Different behavior of sed with respect to an array and a string in the presence of backslashes

Let the file foo.txt contain foo\\ bar baz xx Why does the following correctly change "foo\\ bar" to "someotherstuff" in foo.txt? sed -i 's/foo\\\\ bar/someotherstuff/gI' foo.txt while this ...
1
vote
2answers
64 views

How do you preserve a space in a literal expression in an array value in bash and how to trim down results from a sort command?

In the context of searching for expressions in log files, I was wondering generally if there was a way to quantify and qualify the contents of the logs in /var/log in some way. In particular, does the ...
2
votes
4answers
118 views

Using a generated list of filenames as argument list — with spaces

I'm trying to invoke a script with a list of filenames collected by find. Nothing special, just someting like this: $ myscript `find . -name something.txt` The problem is that some of the pathnames ...
1
vote
1answer
69 views

.bash_profile alias escape quotes?

On the rare occasion I use the command line, I usually forget syntax. This is one of those times. I want to add a simple alias to my .bash_profile but no matter what quote method I use, I get an ...
3
votes
2answers
92 views

Command substitution interpreting spaces within quotes as argument separators

I'd like an alias that additionally appends itself to ~/.bashrc, e.g. function tailias { $(echo "alias $1='${*:2}'" | tee -a ~/.bashrc) } I'm using tee to split the command to ~/.bashrc while ...
5
votes
3answers
73 views

how do I set quotes around a variable so that the programs sees them as quote marks

I am trying to get quotes around a variable to make is just like I typed it in the terminal to get this script to work. it shows " quotes around the varibale " but still does not see it as quotes, as ...
0
votes
1answer
54 views

Could not get a command to work with bash -c

I am trying to execute a command to find out which process is listening on a particular port and i cannot get it to work if the command is passed as an argument to bash using bash -c netstat -tnlp ...
1
vote
2answers
56 views

double-quoting parameter (representing filename) doesn't help if spaces are contained

When iterating over some filenames double-quoting the parameter does not prevent the filename from being broken: $ mkdir temp $ cd temp/ $ touch a\ b $ for f in $(find .) ; do echo "$f" ; done . ./a ...
5
votes
3answers
258 views

cp doesn't work in script but works in terminal

Now, this is a strange problem, I have this kind of script: CWD="$(cd -P -- "$(dirname -- "$0")" && pwd -P)" RESOURCES_PATH="${CWD}/resources" PROJECT_NAME="something" ...
1
vote
2answers
139 views

What does this regex mean?

I was working on the conversion of Unix newline to Windows newline. I tried to unix2dos but it gave me some binary error, so I looked it up and stumbled upon this regex sed 's/$'"/`echo \\\r`/" ...
4
votes
2answers
105 views

Word-splitting when parameter is used within command substitution

What needs to be done to ensure that a parameter containing embedded spaces is handled correctly when used within a command substitution? Perhaps an example will illustrate $ file="/home/1_cr/xy z" $ ...
9
votes
2answers
265 views

Are quotes needed for local variable assignment?

Can I safely omit quotes on the right side of a local assignment? function foo { local myvar=${bar} stuff() } I'm mainly interested in bash, but any info on corner cases in other shells are ...
1
vote
1answer
123 views

What is the difference between ' and "? [duplicate]

I tried to create a text file in a bash script. The echo command spans multiple lines and has some double quotes "". #!/bin/bash echo "blabla bla bla bla "blabla" bla bla " bla bla bla" and so on ...
1
vote
1answer
631 views

bash: export: `--wait': not a valid identifier

When I run git-sh from my terminal it works fine. But I get the following warning. bash: export: `--wait': not a valid identifier What is this and how do I get rid of it?
0
votes
1answer
608 views

Decrypt file using gpg in batch mode when passphrase includes a “!”?

I am trying to decrypt a file in a script with gpg batch mode, but command is not executed because the passphrase contains a "!" echo "m!pass"|gpg --batch --passphrase-fd 0 --decrypt-file plain.gpg ...
2
votes
3answers
421 views

Quote a variable in shell script “if” statement

e.g. if [ "$FOO" = "true" ]; then vs if [ $FOO = "true" ]; then What is the different? Seems both of two statements also works.
2
votes
4answers
254 views

Why is bash interpreting characters that I have character escaped? [duplicate]

Why is it that when I run curl against a REST API, the special characters (!) in my key are interpreted by the shell? curl https://foo.my.salesforce.com/services/data/v28.0/ -H "Authorization: ...
2
votes
1answer
250 views

Screen escape dollar sign

I'm trying to run a command using screen which contains the dollar sign, but the dollar sign does not get through. screen -d -m echo \$ > test.txt test.txt just ends up being an empty file...
3
votes
2answers
563 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
241 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
474 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
83 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 ...
4
votes
2answers
257 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
104 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 ...
2
votes
2answers
109 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 ...
1
vote
1answer
239 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 ...
1
vote
2answers
87 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 ...
5
votes
2answers
262 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
380 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 ...
2
votes
1answer
79 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 ...
2
votes
2answers
620 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
1answer
548 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
306 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 $ ...
0
votes
1answer
212 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 '".*"' ...
10
votes
1answer
480 views

When is double-quoting necessary?

The old advice used to be to double-quote any expression involving a $VARIABLE, at least if one wanted it to be interpreted by the shell as one single item, otherwise, any spaces in the content of ...
4
votes
4answers
823 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 ...
2
votes
2answers
487 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
223 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 ...