Commands by programmer (5)

  • Create a bash script to change the modification time for each file in 'files.txt' such that they are in the same order as in 'files.txt' File name for bash script specified by variable, 'scriptName'. It is made an executable once writing into it has been completed. Show Sample Output


    1
    scriptName="reorder_files.sh"; echo -e '#!/bin/sh\n' > "${scriptName}"; cat files.txt | while read file; do echo "touch ${file}; sleep 0.5;" >> "${scriptName}"; done; chmod +x "${scriptName}";
    programmer · 2016-04-19 11:52:00 3
  • Removing Course name prefix added Show Sample Output


    1
    ls *.pdf | while read file; do newfile="${file##CS749__}"; mv "${file}" "${newfile}"; done;
    programmer · 2016-04-19 11:06:43 5
  • Adding course name prefix to lecture pdfs Show Sample Output


    1
    ls *.pdf | while read file; do newfile="CS749__${file}"; mv "${file}" "${newfile}"; done;
    programmer · 2016-04-19 11:04:47 3
  • retrieve file names back from touch commands for them Show Sample Output


    1
    touch files.txt; cat reorder_files.sh | while read line; do x=`echo $line | sed 's/touch \([a-z0-9\.]\+.*.pdf\);.*/\1/'`; echo $x >> files.txt ; done;
    programmer · 2016-04-19 11:01:17 1
  • useful to find the list of dependencies Show Sample Output


    2
    jar -tf file.jar
    programmer · 2010-10-13 10:53:07 0

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Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Remove a line from a file using sed (useful for updating known SSH server keys when they change)

Securely stream (and save) a file from a remote server
Securely stream a file from a remote server (and save it locally). Useful if you're impatient and want to watch a movie immediately and download it at the same time without using extra bandwidth. This is an extension of snipertyler's idea. Note: This command uses an encrypted connection, unlike the original.

recursive search and replace old with new string, inside files
xargs deals badly with special characters (such as space, ' and "). To see the problem try this: touch important_file touch 'not important_file' ls not* | xargs rm Parallel https://savannah.nongnu.org/projects/parallel/ does not have this problem.

positions the mysql slave at a specific master position
say you want to reinitialize the slave database without resetting the master positions. You stop the slave, dump the master database with --master-data=2 then execute the command on the slave and wait for it to stop at the exact position of the dump. reinit the slave db and start the slave. enjoy.

create a colorful 田 image

Find out current working directory of a process

Copy specific files recursively using the same tree organization.
This command has been used to overwrite corrupted "entries" files of a corrupted subversion working copy. Note the --files-from input format.

Rsync between two servers
copying files from one server to another using rysnc. Root access need to be allowed on the destination.

Show LAN IP with ip(8)
$ ip address show | grep eth0 | sed '1d' | awk '{print $2}' does the same, but shows network-prefix.


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