Linux Tools

Or useful things about Linux I'm sure to forget...

• a2ps

  Use for printing ascii files. ex. a2ps README.txt. This will send the file to the default printer. To check a file first, print to display, e.g. a2ps -P display README.txt. Change the font size to 6 with -f6 option. Show man pages with man pdiff | a2ps -P display. a2ps isn't installed on AlmaLinux. Use enscript

• atom

  Use for profiling executables with hierarchial tracking. ex. atom bmadz_g -tool hiprof -toolargs="-hiout textout -textout -calltime". Then run the created executable, e.g. bmadz_g.hiprof, and look at textout.hiout.

• awk

  A pattern matching programming language.

• baobab

  A graphical display of disk space usage.

• chgrp

  This changes the group ownership of files or directories. To change the group of a directory and its subdirectories: chgrp -R groupname dirname. This is the equivalent of a chown command: chown -R :groupname dirname

• convert

  A very useful image conversion and manipulation command line program. For instance: enlarge an image with convert -geometry 150% bmadz.png bmadz.png, or rotate 90% by convert -rotate 90 image.png rotated.png. To convert ps to png, convert -density 100x100 image.ps image.png seems to produce reasonably sized images.

• cron

  Intro. to cron. Allows repeat execution of programs at scheduled days and times.

• cxx

  The HP C++ compiler and linker. Here's a HP reference page. gcc should be used instead.

• df

  reports file system disk space usage. df -a shows all attached disks, even dummy ones.

• enscript

  a replacement(?) for a2ps. Formatting needs to be specified: enscript -Ef90 programs/test.f90 to format as Fortran f90. Get possible formats with enscript --help-highlight

• find

  Find files or directories recursively. find /nfs/acc/user/mjf7 -daystart -atime -1 -name *tao* will find any file or directory with tao in it that is newer than yesterday 00:00. find . -name \*~ -exec rm {} \; will find all files ending in ~ in all subdirectories of the current directory and remove them. The {} is a place holder for the current file found and bash needs the ; escaped. For this and other examples

• gimp

  Gnu Image Manipulation Program

• gmake

  Here's a sample makefile for a simple C++ program. Note the last target is to create an implicit rule for creating .o files from .cxx files. (The predefined standard for C++ source is .cc)

• jalbum

  Creates and maintains web thumbnail pages. (Needs to be downloaded on unix side. JAC is using on linux.)

• ladebug

  HP unix and linux debugger. Here's the HP Page. It is said to be vastly inferior to totalview (see below)

• ldd

  This prints the shared library dependencies of a program. Very useful in showing problems with the LD_LIBRARY_PATH environment variable.

• lpc

  Access the printer spool manager. Give command status to get a list of printer queues.

• lynx

  text-based web browser. (replaced elinks?)

• ncdu

  NCurses Disk Usage disk utility program. nice -n 9 ncdu -x ./ will map the disk usage in the current directory without leaving the filesystem.

• newgrp

  Change current group to a new group.

• nm

  Looks through object files for symbols. You can look through object libraries for a particular symbol, as in: nm libsomelib.a | grep some_obscure_symbol. A U next to the symbol means it is undefined, in other words, there are calls to it. A T means the symbol is in the text, most likely meaning that it is defined in that library.

• nohup

  Runs a program ignoring hangups and quits and logouts.

• paw and paw++

  Physics Analysis Workstation -- a data manipulation and graphing program. See its online site.

• renice

  Change the priority setting of a process after it has started. renice 4 -p pid sets a nice setting of 4 to the process with pid number of pid. Or use renice 4 -u mjf7 to change all of mjf7's processes.

• sed

  powerful stream editor.

• ss

  socket statistics. Display and monitor the local computer's socket information. Ex. while true ; do sudo ss -tp | grep \\.1\\.10:; done will loop showing processes using tcp sockets with an IP ending in .1.10:

• tac

  Prints a file in reverse (reverse of cat...) tac test.txt > test.rev will create the file test.rev that is the reverse of test.txt.

• totalview

  This is the expensive gui debugger. Invoke with: totalview bmadz_g -a cons.in new_bmad_input.

• tr

  Translate characters. tr '\0' '\n' < /proc/16878/environ to look at the environment that a process was started with. (From the gospel of DSR).

• tree

  display directory structures as a tree.

• xfig

  Creates and modifies figures. (labels...)

• xlsfonts

  Lists the available x-window fonts.

• xrdb -query

  Lists the current x-window resources.

• zenity

  Pops up different gtk+ dialog displays for use in scripts.

Miscellaneous Info

You can get a list of available node names by going to cesr38 and looking at /etc/hosts -- but perhaps better is host -l lns.cornell.edu

I was able to get rid of an error (size_t) while running configure, by changing the CC environment variable from cc to gcc.

To start a job in unix so that logging out won't stop the job, add >& outputFileName & to the command. This redirects stdout and stderr to the output file and run the job in the background.