Commands by alcik (4)

  • You can use wildcard with rpm search but you have to do 2 things: 1. use "-a" switch (means "all") with query ("-q") switch - argument is a pattern to use while searching for package names of all installed packages 2. protect wildcards, so that shell could not eat them - escape it with backslash ("\") or enclose all pattern between apostrophes ("'"): rpm -qa 'co*de' As you can see above it is possible to insert wildcards into middle of the pattern. If you want, you can add "-i" or another rpm query options, "-i" will print package information for all installed packages matching pattern. Show Sample Output

    rpm -qa \*code\*
    alcik · 2009-03-11 21:16:23 1
  • This example summarize size of all pdf files in /tmp directory and its subdirectories (in bytes). Replace "/tmp" with directory path of your choice and "\*pdf" or even "-iname \*pdf" with your own pattern to match specific type of files. You can replace also parameter for du to count kilo or megabytes, but because of du rounding the sum will not be correct (especially with lot of small files and megabytes counting). In some cases you could probably use sth like this: du -cb `find /tmp -type f -iname \*pdf`|tail -n 1 But be aware that this second command CANNOT count files with spaces in their names and it will cheat you, if there are some files matching the pattern that you don't have rights to read. The first oneliner is resistant to such problems (it will not count sizes of files which you cant read but will give you correct sum of rest of them). Show Sample Output

    SUM=0; for FILESIZE in `find /tmp -type f -iname \*pdf -exec du -b {} \; 2>/dev/null | cut -f1` ; do (( SUM += $FILESIZE )) ; done ; echo "sum=$SUM"
    alcik · 2009-03-05 17:16:52 3
  • It displays, last 15 yum operations (in last operation as first row order) with its dates. Change 15 to any number of operations you need to display or remove "| tac" to see it in reverse order (last operation as last row)

    tail -n 15 /var/log/yum.log | tac
    alcik · 2009-03-02 08:56:04 1
  • Replace 'more' command with any command which is in your PATH. Show Sample Output

    rpm -qif `which more`
    alcik · 2009-02-27 08:59:07 2

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Get the total length of time in hours:minutes:seconds (HH:MM:SS) of all video (or audio) in the current dir (and below)
change the *.avi to whatever you want to match, you can remove it altogether if you want to check all files.

umount --rbind mount with submounts

Print your cpu intel architecture family

Prepare B&W scans for clean looking, searchable PDF
Scan pages in, clean them up in an image editor, save to individual files. Use this command to convert each page to PDF. Combine in Acrobat Professional, and use the built-in OCR with the "Searchable Image (Exact)" option. Gives excellent image quality and file size (avoids awful JPEG image recompression that Acrobat and other OCR systems tend to do.)

Compute the numeric sum of a file
In the file data.txt there is a single column of numbers. Sed adds a "+" between lines and xargs prepares the output for bc. The "echo 0" is to avoid to have a "+" at the beginning of the line.

Search specified $TEXT1 and Replace that by specified arg ($TEXT2)

Change Title of Terminal Window to Verbose Info useful at Login
I usually have 5 or more ssh connections to various servers, and putting this command in my .bash_profile file makes my putty window or x terminal window title change to this easily recognizable and descriptive text. Includes the username, group, server hostname, where I am connecting from (for SSH tunneling), which device pts, current server load, and how many processes are running. You can also use this for your PROMPT_COMMAND variable, which updates the window title to the current values each time you exec a command. I prefix running this in my .bash_profile with $ [[ ! -z "$SSH_TTY" ]] && which makes sure it only does this when connecting via SSH with a TTY. Here's some rougher examples from $ # If set, the value is executed as a command prior to issuing each primary prompt. $ #H=$((hostname || uname -n) 2>/dev/null | sed 1q);W=$(whoami) $ #export PROMPT_COMMAND='echo -ne "\033]0;${W}@${H}:${PWD/#$HOME/~} ${SSH_TTY/\/dev\//} [`uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g"`]\007"' $ #PROMPT_COMMAND='echo -ne "\033]0;`id -un`:`id -gn`@`hostname||uname -n 2>/dev/null|sed 1q` `command who -m|sed -e "s%^.* \(pts/[0-9]*\).*(\(.*\))%[\1] (\2)%g"` [`uptime|sed -e "s/.*: \([^,]*\).*/\1/" -e "s/ //g"` / `command ps aux|wc -l`]\007"' $ #[[ -z "$SSH_TTY" ]] || export PROMPT_COMMAND $ #[[ -z "$SSH_TTY" ]] && [[ -f /dev/stdout ]] && SSH_TTY=/dev/stdout And here's a simple function example for setting the title: $ function set_window_title(){ echo -e "\033]0; ${1:[email protected]$HOST - $SHLVL} \007"; }

Restore deleted file from GIT repository
This command will automatically find the latest version of the file that was deleted and restore it to it's previous location. If, of course, your file was kept in a git repository... I found this command on

Backup with versioning
Apart from an exact copy of your recent contents, also keep all earlier versions of files and folders that were modified or deleted. Inspired by the excellent EVACopy

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

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