The shell is unix's command-line interface. You can type commands in a shell interactively, or write scripts to automate tasks. Use this tag for questions applying to /bin/sh and most compatible shells (ash, bash, ksh, zsh, …).

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6
votes
1answer
444 views

Output redirection and spaces

I'm paranoid about this, but hopefully it's a simple question: Is there any difference between cat file1 | egrep -oP "[Mm]y string" > /home/user/file.txt and cat file1|egrep -oP "[Mm]y string"&...
9
votes
4answers
10k views

How to embed a shell command into a sed expression?

I have a text file with the following format: keyword value keyword value ... Where keyword is a single word and value is everything else until the end of line. I want to read the file from a shell ...
2
votes
1answer
1k views

Running sha1sum into several directories

I have several directories that share a common parent directory. In each directory there are regular files, but no other subdirectories. Something like this: top/dir-1 top/dir-1/file-11 top/dir-1/...
1
vote
1answer
844 views

Regular expression how to get value in shell script?

I have to write a shell script to get value from a string, something like: string="abcdef" pathName How can I use grep command with the use of regular expression to get "pathName"?
1
vote
2answers
2k views

Parsing the output of date with sed

I am trying to replace the whitespaces in the output of date with '_' with no success. $date Fri Sep 14 14:10:04 EDT 2012 $ date | sed 's/ /_/' Fri_Sep 14 14:10:24 EDT 2012 As you can see, the ...
8
votes
3answers
27k views

Recovered deleted files on Mac by command line

I accidentally deleted a file by running: rm -rf ./Desktop/myScript.sh I think it's possible to recover the file, because the rm command removes temporarily. How can I recover the deleted file on ...
1
vote
1answer
107 views

Redirection doesn't show up as an argument to a sourced script

My problem is that I can't print to the screen when I write a bash script . myBashScript.sh < text.txt In myBashScript.sh I just print out echo $2 But instead of printing "text.txt", it ...
2
votes
2answers
948 views

Create a new link to access all files and folders

I get stuck to create a shell script for a new link something like that link linkPathName orginalPathName I want to create a link between a new link and original path; however, both can access ...
2
votes
1answer
113 views

Why is return is ignored during output in bash?

When I start a program that runs for a bit, say make, I could just type the next command in bash even before I got a prompt back and when the first command finished, the second one was executed as if ...
3
votes
2answers
425 views

Am I using bash after this ordeal?

On Mountain Lion, host Coguaro, I login as user coconutpowder using bash: Coguaro:~ coconutpowder$ echo $0 -bash I need to run a command with elevated privileges so I try to su switch to root but ...
5
votes
3answers
1k views

id3v2 used recursively at command line?

Trying to get my id3 tags cleaned up and am loving id3v2 on the command line -- but I've been using it only with a *.mp3 wildcard and want to explore if there's a way to use it recursively so I can ...
3
votes
3answers
6k views

Split command output by linebreak?

I have a command returning multiple lines. For further processing I need to process each single line of those lines. My current code works by modifying the IFS (Internal Field Separator): ROWS=$(...
8
votes
2answers
24k views

How can I search a wild card name in all subfolders?

How can I search a wild card name in all subfolders? What would be the equivalent of DOS command: dir *pattern* /s in *nix?
18
votes
3answers
21k views

Is there a simple command for outputting tab-delimited columns in bash?

E.g. I have a file (produced with echo -e "var1\tvar2\t\var3\tvar4" > foo) that are output (in bash): $ cat foo case elems meshing nlsys uniform 2350 0.076662 2.78 non-conformal ...
3
votes
4answers
638 views

Piping paths with different types of quotes for slash substitution

I would like to use sed to convert a path with backslashes to the same path with forward slashes: E.g. I would like to pipe \\path\to\file\ and obtain /path/to/file None of the following commands ...
23
votes
9answers
8k views

Bash commands inside vi

Is it possible to type a bash command inside vi and get the stdout? I find it often tedious to close and reopen vi just because I want to look something up in the shell.
8
votes
3answers
5k views

How can I do the equivalent of tail -f with ls? [duplicate]

Possible Duplicate: Is it possible to follow a command (run repeatedly)? as one would follow a file using tail -f? I would like to monitor files that are being downloaded to a directory in ...
0
votes
2answers
675 views

source script as command [closed]

For some reason (?), often when I write scripts nowadays they do not work, or work only in part, and then I try with . or source and they work perfectly. I'm unsure what is causing this as the scripts ...
2
votes
1answer
749 views

Command substitution: file or command not found

The following script #!/bin/bash QUERY='select * from cdr;' MYROWS=$("sqlite3 -list -nullvalue NULL -separator ',' /var/log/asterisk/master.db '${QUERY}'") gives me ./bla.sh: row 35: sqlite3 -list ...
6
votes
2answers
2k views

What is the best way to find a list of several strings within a large text file

The short, general question is: In Unix/Linux, what is the best way to find a list of several (about 150) strings within a large text file? I am asking this to all Unix/Linux experts as a general ...
4
votes
3answers
2k views

shell script to read from multiple files in parallel

I need to write a script that runs parallel and looks for a string in multiple files. I tried a lot of options but they slow down the speed of my processor.
2
votes
1answer
204 views

How to run a command against all the files of particular types on a filesystem?

I've just recovered tons of files (distributed in a complex directory structure, having very long names, using Unicode symbols, spaces etc in names) from a damaged hard drive. Now I'd like to verify ...
0
votes
1answer
6k views

Script failing with “command not found: ^M”

When I try to run the following script in zsh, via the command /bin/zsh ~/.set_color_scheme.sh I get the following error: command not found: ^M The script has u+x permissions and it used to work on ...
0
votes
2answers
532 views

Installing a shell (e.g. zsh) without being system admistrator [duplicate]

Possible Duplicate: how can I use bash as my login shell when my sysadmin refuses to let me change it Say I have rwx permissions to a directory (my home directory). Can I install a shell (e.g. ...
3
votes
1answer
609 views

Extract directory from wget's stdout

I am trying to wget a tarball from github.com and, without creating a temporary file, extract a subdirectory from it: wget -qO- https://github.com/django-nonrel/django-nonrel/tarball/develop | tar ...
26
votes
4answers
22k views

How to Execute multiple command using nohup

I need to execute multiple commands using nohup. Each command should be executed after the previous command. I used this command as an example: nohup wget $url && wget $url2 > /dev/null ...
16
votes
3answers
13k views

Can files be created with permissions set on the command line?

When creating directories, mkdir -m <mode> <dir> provides for creating one or more directories with the given mode/permissions set (atomically). Is there an equivalent for creating files, ...
1
vote
1answer
84 views

Social website about shell commands

I remember seeing an entire social website devoted to the question What are your favorite command line features or tricks?, where you can post shell commands, tag them, comment on them, and rate and/...
5
votes
2answers
20k views

Execute shell script from php, as root user?

Need to execute the following line from PHP: $res = shell_exec('sudo sh /home/nicklas/cronjobs/make_account.sh username password'); The problem is nothing happens on execution. If i try to ...
3
votes
1answer
715 views

Shell script to execute a command with iteration

This is a script which looks for .tab files in a folder an should imports them with ogr2ogr, but I fail with the correct bracing. for i in $( ls *.tab ) do echo item: $i ogr2ogr -f PostgreSQL -...
9
votes
3answers
455 views

How can my script know when I'm in a virtual console vs. an xterm?

A few of my scripts (keymap changing, public key adding) need to act differently when in a virtual console vs. in an xterm. What's the real code for #!/bin/ksh if [[ in_a_virtual_console ]]; then ......
2
votes
3answers
574 views

Return value of commands when using stdin?

Imaging I am executing the following command: echo "root:mypass" | chpasswd How can I get the return code / error code returned by chpasswd? Is that possible in this case at all? I tried RET = `...
6
votes
2answers
10k views

Passing arguments with quotes and doublequotes to bash script

At this moment I have: #!/bin/bash screen -p 'ScreenName' -x eval 'stuff '"'"$@"'"'\015' echo eval 'stuff '"'"$@"'"'\015' But when I call my script as: # script.sh asd "asd" 'asd' my arguments ...
1
vote
1answer
573 views

Shell variables not working?

I'm trying to store the date in a variable ($DATE) so I can use it later, but it doesn't seem to work. See anything wrong? DATE=$(date +"%Y-%m-%d %R") sudo mysqldump -u root -pnotgivingyoumypassword -...
-1
votes
1answer
7k views

Bash function to compare two binary files [closed]

I need a function to compare 2 binary files, here the requirements: 2 files, not 3 or 4 files can't be assumed to exist avoid running checksum (CRC/MD5/SHA/...) until one must if running multiple ...
3
votes
1answer
2k views

Is it a bug for join with -t\t?

I have a problem with the command join. "The default join field is the first, delimited by whitespace" (Cited from join --help). However, there is a field containing sentences in my tab-delimted files....
3
votes
1answer
3k views

How to move file based on file name expression using shell script?

I want to achieve the following using a shell script. When a script is called with a file as a parameter, it should move the file based on a portion of its name. For example, "Car insurance ...
3
votes
2answers
2k views

How to pass a variable to an sh child process? [duplicate]

Possible Duplicate: How to “send” variable to sub-shell? I have a bash script and inside that script I do sh. How to pass a variable to the new shell? This is how it is (simplified ...
8
votes
5answers
8k views

Check if script is started by cron, rather than invoked manually

Is there any variable that cron set when it's running a program ? If the script is running by cron, I'll skip some parts; otherwise invoke those parts. How can I know if the bash script is started by ...
9
votes
1answer
17k views

Executing a script in zsh - file permissions

I'm confused about execute file permissions not behaving as I expect. Probably because my expectations are wrong. Anyway: I have a script file, for simplicity is just called s, located in ~/bin. For ...
1
vote
5answers
12k 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 ...
25
votes
4answers
18k views

how can I use bash as my login shell when my sysadmin refuses to let me change it

The unix sysadmin where I'm working is reluctant to give me access to change my login shell from ksh to bash. He has given various excuses, the funniest being that since they write all their scripts ...
1
vote
3answers
4k views

how to sum output of awk or other expression with xargs

Suppose i have the following bash shell script: #!/bin/bash export count=0; for i in `ls ./mydoc` ;do pdfinfo ./mydoc/$i | egrep Pages |awk {'print $2'} |xargs -+ $count ; ...
3
votes
2answers
3k views

exec < filename - what does this do?

I have found the following code snippet (sh): TESTFILE=$TEST_PATH/test.out if [ -f $TESTFILE ] then exec < $TESTFILE else echo "$TEST_PATH: no test.out file" fi ...
1
vote
2answers
2k views

Have bash script wait for password

I want to write a little script which sets up a socks proxy via ssh and then starts a browser using that proxy. #!/bin/bash ssh -D 1234 user@host #& chromium-browser --proxy-server="socks5://127....
2
votes
2answers
3k views

Cron to delete particular file(s) from a specific directory

I am new to shell scripting. I am trying to write a cron for unix shell that will delete some files, say after 2 weeks or after 1 month from a specific directory. /somedir1/somedir2/ if(somedir2) ...
2
votes
3answers
3k views

Switching to superuser while shell script is running

I have a shell script that contains the following lines: CURRENT_USER=${USER} echo $CURRENT_USER su echo switch to `who am i` Once the 2nd line is executed, the shell prompts me to enter the root ...
7
votes
2answers
10k views

Why Bash unable to find command even if $PATH is specified properly?

I am specifying path to my command in the file /etc/profile: export PATH=$PATH:/usr/app/cpn/bin My command is located in: $ which ydisplay /usr/app/cpn/bin/ydisplay So, when I performing "echo $...
3
votes
2answers
1k views

Remove 50GB oldest files in busybox when used capacity reaches 95%

Ok i have requested a code here but initial i didn't ask to make it busybox compatible. My bad. I'm new to linux and coding. The code needs to do the following: Delete 50GB of oldest data (dir ...
1
vote
1answer
528 views

show only tags of an xml document on the command line

Is there a command line command or utility I can use to show only the tag structure of an xml document? I looked at xmllint but I didn't see a switch to do it. For a structure like <tag1><...